Why not try them both and see which one works best for YOU.
As you've said, there will be people that are totally happy with spreadshirt and people that are totally happy with cafepress (and people that love both).
I've used both and I think they both provide great services. It's all up to your preference.
Your biggest mistake would be to do nothing instead of to just click and try it out
Both CafePress and Spreadshirt use
DTG printing. CafePress has been doing
DTG longer than spreadshirt.
Maybe if you had a specific question about either service, people could answer those for you