Board Thread:Warhammer 40k General Discussion/@comment-66.206.224.153-20131222032846/@comment-9676764-20140219133855

I'd say that in general the Ultramarines were the most combat effective, because most other chapters are excellent at one thing (Imperial Fists are siege men, White Scars are fast, etc) whilst the Ultramarines are supposedly great at everything.

But defending things, I'd agree that an imperial fist army would probably be a safe option.