Class A 30 Watt Amps: Are they enough to drive my book shelfs?

For those folks with experience listening to 30watt class A amps, how would the Pass Labs XA 30.5 compare sonically to the pass labs 150.5 A/B amp?  Other than more power & better bass control (with the 150.5) is there a unique listening experience (with pure class A) worth chasing?

BTW- thanks for the previous thoughtful responses on this.  

Since it looks like nobody asked this question, why would you want to invest in a class A amp to drive KEF bookshelf speakers? Dynaudio or the equivalent maybe, but KEF? Better off to invest in better speakers and live with a class AB amp; much better bang for your buck.

The class of speaker is independent of the brand. 

@almarg 
Al, remember that there are two speakers, not one (+3dB).    Room gain adds +3dB (or more)  and I'm sitting at about 3m from the speakers equal to loss of a little more than 6dB (9.5dB?).   Rule of thumb has -3.5dB error here, but works perfectly for 2m listening distance.  Almost constant loudness in my room is likely because of listening angle to the speaker.  When I get close to one of them the other is at an angle and when I get closer to front wall between the speakers both are at angle.