I've been dealing with TSC for at least 4 years...
Far and away the biggest problem they have is with their help and their being able to stock the most requested items...
They hire local help and obviously do not train them well...I find that most of the employees are middle aged women with backgrounds in keeping horses etc...
Now for the good points (that I think out-weigh the cons)
Buy something in one store and there is no issue returning it to any other TSC...
The quality of their tools etc is very good...I have been using one of their home brand (name escapes me at the moment) 4.5" angle grinders for 3 years and am more than satisfied (I usually go through a quality grinder in 18 months)...and it came with an 8' cord....
In many rural areas there is virtually no source for hydraulic fittings, hoses etc...many users have no idea what they need to order via the Internet....they need a place where they can take a leaking hose/fitting and matche it up with something that will work...TSC is there...
Run out of welding rods/wire etc... in many areas there is a TSC a lot closer than a welding supply or a Home Depot...
They may not be the best store in the world but they definately fill a niche...
This year I have a new TSC store that's opened 25 miles closer than the one I previously patronized....so now it's ony a 50 mile round trip...but I'm glad i'ts there...