definitely rubber!!

i find that the acrylic ones do not always give a solid coverage of ink when stamped. i do use some acrylic if i cannot find similar designs in rubber stamps, but otherwise i use rubber ones.

Rubber, wood mounted first, then TAC style with the cushion and rubber. Hve not had any luck with acrylic and have never tried photopolymer yet.

Acrylic is the material of the actual block; photopolymer is what (high-quality) clear stamps are made of. Lower-quality clear stamps are made with silicone I think.

I really prefer mounted rubber stamps; however, I only have a few unmounted acrylic stamps and have played with them very little. I didn't really like them but I don't think I gave them much of a chance. I haven't tried unmounted rubber but I love Gina K's stamps and I might have to jump in and give it a try!

BOTH...
 

I like them all! I love my SU mounted stamps, but I'll probably unmount them for storage. I also find I rarely use them because it's so hard to go through all the boxes to find the one I want. So I will likely use them more if I unmount them. I'm terrible at placement and can't remember how to use my Stampamajig :). They work well with all my SU and CTMH inks. I have mixed feelings on my CTMH stamps. They sometimes give me a cruddy image and they just smell so stinky! But I like the designs--hate they way they smell. I have 3 sets of PTI stamps and pretty much love them. But I can't get the Palette inks to give me a good image (I think I just need more practice), so I use my Versamagic (love these inks). I also love, love, love the Fancy Pants clear stamps with chalk inks. And I like my unmounted rubber stamps, too. Nice quality at affordable prices. I have some from Cat's Life Press and Purple Onion. So, I like them all, but I plan to unmount the rubber ones...

Nichole Heady from PaperTrey Ink has some tips on her blog about using Palette Ink. They seem to take a while to "set".. HTH =)
http://nicholeheady.typepad.com/capt...p-nextink.html