I have a Wagner Paint Crew (the old one, not the Plus which looks like a pressure washer), and it's actually pretty decent for how much I paid for it - $200. Sure, it's crap compared to contractor grade stuff, the sprayer is pretty cheap, the hose doesn't have a swivel, etc., but again, you get what you pay for.
The hose/sprayer/tips/etc are all standard size, you can easily augment the kit with some better gear if you want to. Biggest limitation is that the hopper only holds about 2 gallons IIRC. The pro gear connects directly to 5gal cans of paint so no pouring and longer spraying between changes.
I painted the outside of my entire house with one a few years ago, and other than having to replace the spray tips a few times, the system performed admirably. I also used it to paint my living room with vaulted ceilings, and a few other larger areas of the interior of my house.
If I was going to do a LOT of projects, I'd buy an entry level contractor sprayer, but for occasional jobs, it's fine.
I have ZERO experience with their smaller units or any of their other gear.
This is the one I have:
Paint Crew