It depends on the year of the bike. The XR 250 L, which is the newest, has a taller 5th and 6th gear internally.
They all have taller external gearing (I think one size larger on the front sprocket, and maybe one tooth more on the rear).
The bike has decent power in stock form. They will go anywhere you want them to, but would have problems on tough hillclimbs, mud or sand washes.
Compared to a modern (1997 or later) XR 250R, they have about 4 less horsepower in stock form, and weigh about 18 pounds more (I don't know this exact number - maybe someone else does).