Verizon is definitely compressing signals in the 3 to 1 statmux transition. It started with provider delivered MPEG-4 channels such as HBO and Cinemax. These had to be re-encoded anyway for MPEG-2 delivery on the Fios network and were only being sent at a bitrate of 6 MB/sec in MPEG-4 (roughly 12 MB/sec in MPEG-2). But recently, channels which originate in MPEG-2 from the provider, such as Epix2 HD, have been converted to 3:1 channel loading. If Epix2 originates from the provider as 18 MB/sec, the best Verizon can do with 3:1 statmuxing is 13 MB/sec using MPEG-2 encoding. Most people with HDTVs smaller than 50 inches simply won't notice the difference. Customers with TV sets 80 inches and above probably will object more. Even with 3:1 channel loading, Verizon's picture quality will be much better than ATT's U-Verse IPTV delivery system. Fios picture quality will be on par with Comcast and Time Warner, who have been using 3:1 MPEG-2 statmuxing for 5 years.
Currently about 40 of the 130 national HD English cable channels are loaded 3 to 1 on Fios. If another 60 make the transition, this will open up another 10 QAM slots, providing up to 30 additional MPEG-2 HDTV channels. Hopefully the 25 most popular cable networks will remain 2 to 1 MPEG-2 channel loading for sometime.