I have owned and still own a number of H&K's; USP .45, HK45, Mark 23, P7M8 and a .9mm USP Custom Sport.
When I was looking for a 9mm USP, I was really close to buying a USP Tactical, mainly due to the fact I prefer shooting 9mm for practice. However, I was considering the USP Tactical due to the adjustable sights and trigger, which I feel are an asset when shooting different loads, at different distances, plus I really like a nice crisp, clean trigger.
I was having difficulties justifying the added cost, which is considerable when comparing a standard, fixed sight, factory trigger USP 9mm vs a USP Tactical 9mm. Then I managed to come across a new USP Custom Sport 9mm, which includes the adjustable sights and trigger, but with an end of slide barrel, instead of a threaded barrel.
As mentioned above, although the threaded barrel looks cool and offers a slightly longer overall barrel length, it offers nothing else to us Canucks.
When I go to the range, I am 'torn' between taking my German Sig 226, G17 with Vanek trigger, or my H&K USP Target Sport to work with. The USP Custom Sport offers more personal 'tuning' when compared to the others.
My 2 cents, if you want a 9mm H&K with some nice features, and are not looking for a "tacticool" looking piece, go with the USP Custom Sport and save yourself some bucks for ammo!
The H&K recoil system makes it feel like you are shooting 'low recoil' 9mm rounds. A great soft shooting 9 to practice with and shoot.