Julie
I can try to help you answer your question about the difference between SU and CTMH.
The main difference is CTMH uses Acrylic stamps and positions them on Acrylic Blocks ( also called unmounted stamping). SU uses wood blocks and the stamps are adheard to them all the time.
Also CTMH has a variety of paper ( printed and cardstock) in inks up to 60 different colors. The cardstock is white core--maining that when you tear it it is white in the middle. SU has cardstock called solid core.
If you are needing to contact a CTMH Consultant you can go to the CTMH website and see who is available close to where you live.
www.closetomyheart.com
I hope I answered some of your questions. Again between the two companies it is a personal choice. Both specialize in stamping and scrapbook needs but vary in product.
Stamping Hugs
Nora :-D