Re: Advice for first time Ascend purchase
First and foremost, if you can make it down to Ascend for an in-person listen, you should absolutely do so. Nothing beats hearing these in person. Plus Dina is just fantastic.
Now, the difference between the 170s and the Sierra LX is night and day. The 170 is a fine speaker for its price. The LX is a truly exceptional speaker, period—not just for the price. Obviously the LX costs quite a bit more, but the difference between the two is pretty striking.
You might also consider the Sierra1 V2 and a sub. I would definitely audition the LX vs. the S1V2 at Ascend and if you find the difference not that big (other than bass response, which is definitely better with the LX), you might take the money you save and use that to buy a sub. I find the LXs go deep enough for music (and I'm a bassist, so I'm pretty demanding on bass response), but for HT you really want to get even lower than the LXs go, which means you want a sub.
Personally, I'm still waiting on the S1 to S1 V2 upgrade kits to become available so I can hear the LX vs the S1V2 in person...
Luna Duo V2 LR, Titan Horizon V2, and Rythmik L22 & L12 in HT, Sierra-LXs in study, S-2EXs and Duo V2 C in bedroom, S-1 NrTs in dining room, S-1s at work, HTM-200s in kitchen. Brother owns CMT-340s and dad has a pair of CBM-170s.