Obviously, money is not really an object if you could afford a PTW. You're looking for a reliable, durable gun that will hold together well with minimal maintenance and perform at a decent level out of the box.
In that situation, I would wholeheartedly recommend Classic Army as your first choice. They're excellent, durable guns. Nothing else comes close in terms of quality of the externals in that price range. It's a solid gun that you won't have to baby for fear of breaking.
As for internals, you start off with a reinforced mechbox (most stock guns like TM don't have this) and hardened gears. The other internals are all of decent quality, and if you wanted to replace them, you'd be looking at $75 or less for top-shelf aftermarket parts. Internally, CA have had issues in the past with a few minor parts (all sub-$20 parts), but they really stepped up their game in the past couple of years and their guns are top notch performers.
And as recommended by surebet, G&P make some badass guns too. You'll probably pay more than CA, but they're good reliable guns out of the box.