The HK USP45C is a fantastic weapon and is perfect for CCW. It is not too small, but plenty small enough that it disappears under a t-shirt with an IWB holster. It is not IMO too wide to carry IWB.
The recoil is not bad at all - there is a recoil reduction system in the weapon that works wonderfully. It is extremely reliable and accurate. Put night sights on it and you have a near perfect weapon (assuming it fits your hand).
I carried mine cocked & locked which works very well since the manual safety is in the proper place for a handgun (not where S&W, Ruger and Beretta put most of theirs).
The only drawback I see is that the accessory rail is proprietary, not universal. To put a picatinny railed light on it requires an adaptor, making holster fit an issue. The HK P2000 addresses this, but doesn't come in 45ACP. The new HK45 (or P30, or whatever) will fix this also, but it looks to be larger than the USPC 45.
Overall though... I highly recommend it and it will serve you well.