Now playing: Watch this: Vizio Reference series: Its best TV ever is coming soon?

Thanks to the combination of rock-bottom prices and very good picture quality, Vizio has held down the top spot in our best TVs lists ever since the departure of Panasonic's plasmas.

Now the company has confirmed pricing on the M series and they're some of the least expensive 4K TVs on the market.

Vizio

It has also "introduced details behind" the high-end Reference series TVs that debuted at CES 2014 . It says the TVs will be released by the end of 2015, but didn't announce official pricing. When they do finally arrive, they will apparently be the first TVs with Dolby Vision HDR.

The M series official prices are almost exactly the same as the unofficial, leaked prices from two months ago. The biggest exception is the 50-inch size, which will sell for $799 instead of the leaked price of $899. Here's the full list.

2015 Vizio M series 4K TVs Model Size Release date Price M80-C3 80-inch Later in 2015 $3,999 M75-C1 75-inch Later in 2015 $2,999 M70-C3 70-inch April-May $2,199 M65-C1 65-inch April-May $1,699 M60-C3 60-inch Now $1,499 M55-C2 55-inch Now $999 M50-C1 50-inch April-May $799 M49-C1 49-inch April-May $769 M43-C1 43-inch Now $599

All of the 2015 M series TVs use the same kind of direct ("full-array") local dimming backlights that helped their 2014 predecessors achieve such impressive black level performance. All sizes have the same have 32 zones of backlight dimming, aside from the 43-incher which has 28 zones.

The 60-inch and larger TVs have a "240Hz effective refresh rate" spec, while the smaller models all have a "120Hz effective refresh rate" spec. Since there are no native 240Hz 4K TVs, Vizio has confirmed that those "effective"s indicate that the smaller sets have 60Hz panels, while the larger ones have 120Hz panels, and backlight scanning is somehow responsible for the doubled Hz numbers. It's the same kind of fake refresh rate trickery Vizio and LG have been employing for years.

Just like the P series from 2014, the M series will have five HDMI ports that can accept 4K sources, but only one will be HDMI 2.0 compatible and able to accept 4K sources at 60 frames per second. Meanwhile three of the five will offer HDCP 2.2 copy protection. The M series can stream 4K from Netflix and Amazon Instant Video, like all major-name 4K sets, and also has an app for UltraFlix.

We look forward to reviewing the new M series soon.

Reference series first with Dolby Vision HDR

Vizio also used its M series rollout as an opportunity to reaffirm that the "R is for Reference" series is still a thing.

Sarah Tew/CNET

At CES 2014, the R series basically stole the show, but 15 months later it still hasn't shipped. One of the most impressive R series demos we saw then was for its HDR (high-dynamic range) technology, courtesy of Dolby Vision.

Today Dolby joined Vizio in announcing that the Reference series would be the first TV with Dolby Vision.

Titles enhanced by Dolby Vision will be delivered to the Reference series via Wal-Mart's Vudu streaming service, and an initial slate of titles will be available to R series buyers. Those exact titles were not confirmed, but Dolby says Warner Brothers titles "Edge of Tomorrow," "Into the Storm," "The Lego Movie," "Man of Steel," "Sherlock Holmes" and "Sherlock Holmes: A Game of Shadows," all use 4K Ultra HD Dolby Vision technology. No non-Warner titles were mentioned.

The mouth-watering specs of the Reference series mostly remain intact. It comes in two sizes: 65 and 120 inches. Its HDR is powered by a full-array local dimming backlight with 384 zones and reaches a peak brightness of 800 nits. Vizio touts its wider color gamut but doesn't say exactly how wide, which is a step down of sorts from its initial claim that the set could approach Rec 2020 color. Gamers will appreciate that the set can display 120-frame-per-second content (currently available only from PCs) with

By comparison the Samsung JS9500 , another HDR-capable TV, is said to hit 1,000 nits thanks to an undisclosed number of local dimming zones, and delivers 93 to 95 percent of the P3 color gamut. It's a curved TV (the R series is flat) and has the distinct advantage of actually shipping now, starting at $6000 for the 65-inch size. It's also worth noting that Samsung's current marketing makes no mention of Dolby Vision or HDR. Methinks a format war be a' brewin'.

Originally Vizio told us the R series would ship in fall of 2014, then in the "second half" of 2015. Today's press release doesn't mention availability timing at all, but Matt McRae, CTO and Head of Marketing for Vizio, told CNET it will ship sometime before the end of 2015. He again declined to specify how much it will cost.

Update: Vizio's website originally said the 65-inch set would debut for $4,000, but when we asked Vizio's rep for confirmation, he said that was a mistake. The pricing has since been removed.

Update,April 15 at 5 p.m. PDT: The story has been updated to reflect Vizio's claim that the Reference series would be released by the end of 2015.