Tough choices. I'm a lefty so I really like the P2000/ P30 setup for controls. I have both the P30 (not the L) and a USP in 40 S&W with the safety lever on the RH side. They both feel good but very different in my hand. You don't mention anything about carry so I assume you are looking for the range in which case some of the many refinements found on the P30 may or may not be worth the price difference to you.
The Expert model is likely the ultimate for the range/target/match at about twice the cost of the USP but I have never shot one. Between the P30 and USP quality, reliability and performance I would rank as being equal with ergonomics, asthetics and in my examples the trigger on the P30 being a little smoother. Best bang for buck workhorse I would say is the USP in my humble opinion but again it depends largely on what you intend to use it for. I won't part with either one of mine for what it's worth.