Where are you ordering from, and how many?
You might want to get your most favourite picture done twice in A3 now, once glossy, once satin, put them both on the wall and see what you prefer.
Personally I prefer the 'Matte' style, I have had my prints done by DScolourlabs, and I chose the lustre option (although above this was called gloss!). The texture of the paper reduces most reflections to nothing, apart from a direct light when the picture is behind glass.
DScolourlabs were relatively cheap I thought for an almost a3 print (18x12) ~£1
Postage was quite a bit though, ~£4 (in my mind, prohibitive), but the packaging was worth it, I don't think they are making a profit on the packaging.
I will certainly use them again, but will probably be when I have a lot to print out.