Nala,
H&K's are excellent guns. Are they worth the price? I think yes, but there are very many opinions on this. I almost bought the EXPERT in .45 caliber several months back. The reason I didn't buy it was the price, I didn't have $1,200.00 on hand. I only had $800.00 so I bought the EXPERT's baby brother, the USP .45F. Kermit gives good reasons why the EXPERT is a fine gun, I would add one more reason, all H&K USP's have the double spring recoil reduction system, which reduces the recoil felt by the shooter. I would think if you shoot competetion this would be the gun for you. It has everything you need right out of the box, no need to add/modify anything on the gun. Just buy ammo and have fun.
Flattop