Sounds like a good deal to me Ace

. I'm assuming by price it's possibly the NexStar 5 SE Mak Cass on single-arm alt-az mount? Enough technology there with the motorised mount & GOTO to satisfy you & your son's needs, very portable, and enough aperture to let you see heaps in the night sky!
As far as after-sales goes, well there's always a risk buying OS, but only as far as manufacturing defects covered by warranty goes. For on-going repairs and maintenance, we're all in the same boat - you've gotta pay, and any dealership will do it!
Good luck with it!
Cheers -