Your question about which title to get next is a very common question that we see here all the time.
The "standard" reply is for you to select a title that interests you the most.
I do not own Scheldt '44 however, I believe reading others who posted that there is alot of mud and slow movement conditions found within the game. Bulge '44 has snow in some of the scenarios. Both mud and snow will slow down the pace of the advancement of your units and the speed of your game.
Bottom line, select what interests you the most and don't worry, you'll have no problem finding PBEM opponents here at the Blitz.
If you are addicted to JTS games, just like the rest of us, you will eventually own them all.
Please keep us updated on what you decide.
Good Luck!