I think they both have thier gremlins,I had a 95 ls and a 95 sr, the ls was easier to maintain mostly do to the fact that there were more produced in many different vehicles. They both went over 100k no problem, i decided to trade the ls in and keep the sr, and wouldnt you know the lower end went bad.
My sr is for sale for 1500.00 all it needs is the lower end rebuilt. look for my post 95 sr must go.

As far as off road goes the sr is great but the ls is also better then most out of the box. Both engines benefit from proper maintenance.

Jesse