You can't go wrong with either...

The P30 is the more up to date model from Heckler and Koch... Ergonomics are better
However, the USP is a classic design. I own a USP-C. I got the USP for the classic design.
Youll find a USP online for cheaper than a P30 as well.

Both are equal in reliability (super duper reliability) and have more likeness then differences

If I had to do it all over again, I might have gone with the P30 (was unaware the model existed at the time) but if you cant decide there are a handful of other pistols you could look at too. A Sig Sauer P226, Glocks, etc. But HK is an amazing brand. Hope this helps

i shoot the HK45, which is very similar to the p30 but chambered in 45acp. as Jake said, they are both fantastic weapons. the reason i fell in love with the HK45 was the ergonomics. it fits the hand perfectly, and i find the p30 to do the same.

basicly, both are awsome pistols, and realy all i can suggest is that you go to a gun shop and handle bot of them to see what weapon fits your hand better.

Relatively the same basic design so just choose whichever fits YOU best, which fits YOUR hand best and feels best to YOU.