I have a 4805 and wouldn't call it one of the top 5 projectors under $5000 lol.
It's one of the top 5 under $2000 though.
I agree that projectors have issues. Screen Door Effect is an issue for LCDs and Rainbow Effect is an issue for DLPs. I can see rainbows on my 4805 if I move my eyes very quickly across the 76" image. I'm sitting closer than recommended though, so I think that's partly to blame. The X1 has a slower color wheel and rainbows will be more apparent.
If you're worried about throw, go to
the projector central screen calculator to see if this is right for your room. There are short throw and long throw projectors.... and a lot of variation in between.
Brightness and Light Control are pretty much the same problem. Don't get a projector if you plan on watching it in the daytime in a room with windows you can't cover up. If you're watching at night you don't have to worry. If you have decent shades, that's fine too. I just put cardboard in my windows and can watch anytime I want.
I used to think bulb life was a big deal, but with bulbs for projectors lasting ~3000 hours and costing ~$300, you're paying 10 cents an hour basically. Watching a 2.5 hour movie is only 25 cents worth of bulb life. Even if you watch it a ton (like 8 hours a day), it's still going to last you a year on average.
I'd be kinda worried about buying a used projector due to bulb life though. If there's some way they can fake the bulb hours you would need to factor in another ~$300 into the price. I never really considered buying a used projector though, so I don't know anything about faking bulb life.
Projectors are a technology that has a lot of benefits, but you have to meet several conditions before you should consider one.