Let the guy speak for himself? 
 
The tensile 60 is an awesome freewheel, Mine got abused like mad right from the day I got it and it never skipped on me, Absolutely brilliant. 
 
If you want to keep to a budget, it really is a decent freewheel to go for, and 60 engagements is actually quite a lot. 
 
Then again, if you have the money, the SL has such a good reputation that it's definitely worth a go