This is the first week in history that Americans can get subscription TV, over the Web, without having to sign up for cable. I don’t think it’s the end of traditional pay TV, but I do think it’s a very big deal.

At the very least, this is a fascinating real-world experiment: If you’re not paying for pay TV, will you start paying for Dish Network’s $20 a month Sling TV service, which gives you ESPN and some other channels, delivered over the Internet? If you are paying for pay TV, are you going to swap it out for a combination of Sling TV and some other Web video, like Netflix?

We won’t know the results for months, and likely years. And it will get even more interesting in a few months, when HBO starts Web subscriptions, too, and the notion of building a real “a la carte” TV service becomes a reality.

But I’m eager to get this started, and it’s going to kick off today. Dish says some people who have registered via its Sling.com site will start getting invites at midnight Monday night, and says the service will be widely available in the next couple weeks.

So at a minimum, we’ll start getting reports and reviews from the general public very soon.

In the meantime, I’ve been playing with Sling TV for a few days, so I can offer up my impressions. It’s not a review! Re/code will have one of those once we’ve had a chance to really put this thing through its paces. But for now:

It seems to stream just fine — but better on smaller screens . I tried Sling TV on an iPhone 5s, an original iPad mini and on my 43-inch Samsung plasma TV, via a Roku 3 box. The video quality was fine for all three, but seemed sharpest on my iPhone — both at home, where I’ve got pretty decent (50 Mbps) Time Warner Cable broadband, and on the go, via Verizon LTE. On the bigger screens — particularly on my TV — the image occasionally looked a little stuttery, particularly during live sports. Sling’s website, by the way, doesn’t claim that it’s going to deliver HD-quality streams to your devices. But it does say that its streams should be “virtually indistinguishable from the quality you would find on a traditional pay-TV provider’s HD experience.”

. I tried Sling TV on an iPhone 5s, an original iPad mini and on my 43-inch Samsung plasma TV, via a Roku 3 box. The video quality was fine for all three, but seemed sharpest on my iPhone — both at home, where I’ve got pretty decent (50 Mbps) Time Warner Cable broadband, and on the go, via Verizon LTE. On the bigger screens — particularly on my TV — the image occasionally looked a little stuttery, particularly during live sports. Sling’s website, by the way, doesn’t claim that it’s going to deliver HD-quality streams to your devices. But it does say that its streams should be “virtually indistinguishable from the quality you would find on a traditional pay-TV provider’s HD experience.” It’s about live, for now. Some of the channels that deliver streams to Sling TV, like Scripps’ Food Network, let you pause and rewind shows, or watch them again after they’ve aired. But for now, the only way to stream ESPN or Turner’s networks — including CNN and ESPN — is in real time. If you try to pause the streams or do anything else, you’ll get an error message. Dish executive Roger Lynch, who is heading up Sling TV, says this is a rights issue, and that he expects to get it resolved with Turner over time. For ESPN, though, it’s unlikely to change. I do wonder what that will mean for Dish’s target audience, which has grown up with the idea you watch TV shows when you want to watch them — not when a TV show is “on.”

Some of the channels that deliver streams to Sling TV, like Scripps’ Food Network, let you pause and rewind shows, or watch them again after they’ve aired. But for now, the only way to stream ESPN or Turner’s networks — including CNN and ESPN — is in real time. If you try to pause the streams or do anything else, you’ll get an error message. Dish executive Roger Lynch, who is heading up Sling TV, says this is a rights issue, and that he expects to get it resolved with Turner over time. For ESPN, though, it’s unlikely to change. I do wonder what that will mean for Dish’s target audience, which has grown up with the idea you watch TV shows when you want to watch them — not when a TV show is “on.” You’ll need the right box. Sling TV will stream to most laptops, tablets and phones. But getting it on your TV will require some hardware. For now, that means you’ll need a Roku box or streaming stick, or Amazon’s Fire TV or streaming stick. That also means your Google Chromecast or Apple TV won’t do you much good. While Lynch tells me I should theoretically be able to use Apple TV’s Airplay mirroring feature to get Sling onto my TV, he doesn’t recommend it. And in any case I could never get it to work. Related: Sling is going to give anyone who signs on for at least three months of service a discount of up to $50 to help them buy certain devices like the Roku 3.

Sling TV will stream to most laptops, tablets and phones. But getting it on your TV will require some hardware. For now, that means you’ll need a Roku box or streaming stick, or Amazon’s Fire TV or streaming stick. That also means your Google Chromecast or Apple TV won’t do you much good. While Lynch tells me I should theoretically be able to use Apple TV’s Airplay mirroring feature to get Sling onto my TV, he doesn’t recommend it. And in any case I could never get it to work. Related: Sling is going to give anyone who signs on for at least three months of service a discount of up to $50 to help them buy certain devices like the Roku 3. Keep it to yourself. The pay-TV guys refer to Sling TV as a “personal subscription service,” which is an awkward way of saying: You can only watch a single stream of TV at a time. Which means that if you’re streaming college basketball on your phone, your roommates can’t watch CNN on the TV at the same time. It also means you’ll want to think twice before handing out your login and password to your pals, HBO Go-style.

The pay-TV guys refer to Sling TV as a “personal subscription service,” which is an awkward way of saying: You can only watch a single stream of TV at a time. Which means that if you’re streaming college basketball on your phone, your roommates can’t watch CNN on the TV at the same time. It also means you’ll want to think twice before handing out your login and password to your pals, HBO Go-style. New TV, old ads. This one probably won’t mean much to you unless you’re in the business of buying or selling ads. But for the record: Sling carries a full (unskippable) ad load. That means that when the network you’re watching cuts to commercials on conventional TV, you get an ad break on Sling TV as well. That doesn’t mean you’ll see the same ads: In theory, some of Sling’s programmers may want to show you different ads than they show to a cable-TV audience, though in practice I think they have a way to go before they figure out how to target individual streamers. It also means that in some cases, you may not see any ads at all: When ESPN cut to a commercial break on regular TV, it just showed me an ESPN logo for the duration. Fine with me.

The takeaway: At a bare minimum, Sling delivers what it says it will: A package of ESPN and a dozen other channels, streamed live over the Web, which you can watch anywhere in the U.S. It’s also pretty minimalist: It doesn’t offer the same bells and whistles that a conventional pay-TV service has. Dish’s bet is that there is an audience that will be happy to pay $20 for that. Now we get to find out.