If you drive (which would be my recommendation) beware the bridge toll booths (new bridge) can get a bit busy early evening on a Sunday, so you may want to consider the timing. Also, there are 2 contraflows currently, 1 close to Bridgend, the other on Kenfig viaduct which seem to be causing some problems currently at peak times and also some emergency eastbound carriageway closures (diverted onto A48) overnight this week, so worth checking
www.traffic-wales.com before your journey in case those closures continue.
I can't vouch for the place myself, but I've seen this establishment in Neath recommended by a local car painter (they do lots of very high end cars, so I would imagine their clientele are pretty fussy about their accomm!)
http://www.thebluebellneath.co.uk/ Looks a bit less plastic than the usual chain jobbies!