I have owned an Epson Ex 70 for a few years and have been moderately happy with it save for the black levels. I'm finishing grad school next year so I don't have a big budget, but I am considering upgrading if I can find a decent used/refurb projector.
The first model that I thought about buying is the Optoma HD 20 as it goes on sale every now and then for a great price, but I am concerned about the black levels. The contrast ratio on it is 4000:1/3000/1 compared to my Ex70's 2000:1, how much better is that? Tricks aside, is there a diminishing return on contrast ratios (i.e. it makes more of a difference going from 100:1 to 1000:1 than 1000:1 to 2000:1)? All the reviews I read say the black levels are very entry level. Would I see any significant improvement? Are there older 720p projectors out there I could get for around the same price that have much better black levels? I know the HD66 is popular and cheap, but the contrast ratio is the same as the HD20. I could care less about 3d, but does it throw a better picture?
Secondly, if I buy used, are lcds a safer bet than dlps? I am concerned about all the moving parts in a DLP such as the color wheel that could fail.