I'm local, so should be able to help.
1. I have done the Gorlech trail once before and thought it was excellent, how does the Raven compare to it?
Both are about the same distance, but the Raven takes a little longer and the technical sections are a little more technical. Some of the climbs are a little steeper as well.
2. Is Llandovery a decent place to stay?
Well I am a little biased!
IMO yes its a nice place. Not a huge amount to do, but a great base. Depending on the size of your group I would recommend Penygawse as a good place to stay. Everyone who stays there recommends it. The Cafe is awesome, best coffee in town. If you need more space then I'm not sure where to recommend, the Castle Hotel is the biggest place, but I don't know what its like these days - its been up and down for a while.
Plenty of pubs in Llandovery, spoilt for choice really. The Neuadd Arms in Cilycwm (near Cwm Rhaeadr) is a great pub which fantastic food.