Which amp would you choose and why - Pass Labs XA-25 or First Watt F8?

I'm very interested in Nelson designs and hope to upgrade to his low watt offerings for a smaller room I have. Does anyone have experience with the Pass Labs XA-25 and First Watt F8 amps? Both are rated at 25W. What main differences do they have? Which one has better bass?

Preamp: Cary Audio SLP98
Speakers: Tannoy XT8F (91db efficient)
I would not be too quick to accept that massive power is always better. I have owned massive amps (i.e., Pass x350) in the past. Headroom is nice, but the grace and Beauty of an XA isn’t there. If your objective is loud and slam, or powering planar, then you need that. But for really good bass and midrange an XA or tube amp is better for many people.
@ghdprentice +1

Completely agree and I have had several examples just in my own house. My Leben 15w CS-300xs sounds substantially better than a Cary SLI-80HS (80 watts ultralinear) with my Forte III’s. The Leben also far outperforms my 30w Sudgen A21SE with the same Forte III’s. My Pass XA30.8 (30w) paired significantly better than another Cary 120w amp with my Spendor D7’s. Circuit topology, transformers, impedance matches, etc all matter when it comes to amp/speaker synergy. It really is not as linear as just saying "get all the power you can" to ensure a good sound. That works sometimes, but not in every situation.

i wished it did too but i was able to use the balanced outs on my preamp and balanced cables by using a neutrik xlr to rca adaptor at the amp.  
sounds better than using rca to rca.