Bea talked me out of the 150's as well for my 20.1's (I was going to buy a pair and bi-amp.) She felt I should get Sigfried's but they were out of my price range; I got a pair of 450's which I'm very happy with. Your speakers are about 6db more efficent which (to me) make the 150 very viable. However I only heard the 150 once and never directly compared it to the 450's (but their qualities seem very similar to me.)
Bea is known for recommending VTL's best amps and generally she gives good advice, but I'd leave the 150 on your short list - especially if you liked it before.
Bea is known for recommending VTL's best amps and generally she gives good advice, but I'd leave the 150 on your short list - especially if you liked it before.