Hi, Mike: Both of the speakers you are considering are excellent, but I concur that the Thiels usually present a greater challenge to the front end than the Vandy's. I currently own the Vandy 3A Signatures, which were preceded by the 3A. The amplification chain is all Bryston, which yields a very clean, dynamic sound quality with the Vandy 3A Sig's. I have owned a number of Vandersteen models since the late 1980's, and none have been picky about the choice of amplifier, provided the amp was of decent quality. If your budget allows, I'd try to find a set of used Vandy 3A Signatures (used price is often in the $2500-2700 range). I believe the upper-mids and highs produced by the 3A Sig's show a real margin of improvement over the 3A's that fully justifies the extra expense.
An occasional comment I have noted from owners of Vandy 3A Sig's is that they sound "polite", which may be a problem caused by either room acoustics or the power amp being used. My listening room is rather small, so I listen in essentially a near-field environment, but I can say that my 3A Sig's have NO problems with dynamics or transparency. I believe the 3A Sig's, when matched with a good quality preamp and power amp, will compete effectively with speakers that are much more expensive. The 3A Sig's feature the same tweeter used in the Vandersteen Model 5, plus an improved crossover and matched mid-range drivers. So, you are getting many of the quality improvements of the Model 5 for 1/4 to 1/3 the cost.
I use my Vandy 3A Sig's as the front speakers in my HT setup, combined with a Vandy VCC-1 Signature center channel and Coincident Technology Triumph Signatures in the rear channels. The 3A Sig's have proven excellent in both HT and pure audio use. The 3A Sig's are driven by my Bryston 4B-ST power amp (in bi-wired configuration, using Kimber 8TC speaker cable). The center and rear speakers are driven by a Bryston 5B-ST amp. I suspect that your ATI amp should work nicely with the Vandy 3A's or 3A Sig's.
I could write at some length about the 3A and 3A Sig, but I will simply summarize and say that I have found them an excellent speaker for my listening tastes (jazz, classical, and blues, with occasional rock) and for HT use. At used prices, you would have to spend at least twice as much money to do better.
An occasional comment I have noted from owners of Vandy 3A Sig's is that they sound "polite", which may be a problem caused by either room acoustics or the power amp being used. My listening room is rather small, so I listen in essentially a near-field environment, but I can say that my 3A Sig's have NO problems with dynamics or transparency. I believe the 3A Sig's, when matched with a good quality preamp and power amp, will compete effectively with speakers that are much more expensive. The 3A Sig's feature the same tweeter used in the Vandersteen Model 5, plus an improved crossover and matched mid-range drivers. So, you are getting many of the quality improvements of the Model 5 for 1/4 to 1/3 the cost.
I use my Vandy 3A Sig's as the front speakers in my HT setup, combined with a Vandy VCC-1 Signature center channel and Coincident Technology Triumph Signatures in the rear channels. The 3A Sig's have proven excellent in both HT and pure audio use. The 3A Sig's are driven by my Bryston 4B-ST power amp (in bi-wired configuration, using Kimber 8TC speaker cable). The center and rear speakers are driven by a Bryston 5B-ST amp. I suspect that your ATI amp should work nicely with the Vandy 3A's or 3A Sig's.
I could write at some length about the 3A and 3A Sig, but I will simply summarize and say that I have found them an excellent speaker for my listening tastes (jazz, classical, and blues, with occasional rock) and for HT use. At used prices, you would have to spend at least twice as much money to do better.