It's usable. I have DirecTv and Cablevision so I can compare back to back. For some channels DirecTv is better, others Cablevision is better. Cablevision is better with the local networks like ABC, CBS, etc. On DirecTv a lot of the NY locals look soft, no blockyness.
When it comes to cable nets like HGTV and FOOD DirecTv is better. HGTV and FOOD do suffer from massive blocking with fast motion on Cablevision. Plus there just seems to be breakups from time to time. I believe the breakups are in the feed since my box stats show 0 for corrected and uncorrected errors. Don't see the breakups on DirecTv when comparing the same show at the same time. I'm pretty sure HGTV and FOOD are still 4 per QAM.
The all digital switch did allow me to dump the tuning adapter, that is a huge plus!
TiVo HD with an M-Card
Both STB connected to TV via HDMI