TV vs Projector: Projectors win over Tv on size. However, no projector can compete with a lot of daylight. A TV is much better for rooms where light is an issue.

Ultra HD “4K” projectors: Their resolution is at least 3840×2160 (comapred to  1080p, or 1920×1080 in HD). But they are very pricey and there is still not much 4K content available.

A good modern projector has HD image quality and have the right brightness and contrast ratio. A low contrast ratio means the image will look flat, washed out, and mundane.

Also buy: Projector screesn, especially those that help improve  image brightness.

The Best projector technology: LCD (Liquid Crystal Display) and LCOS (Liquid Crystal on Silicon) vs DLP (Digital Light Processing). Compared to LCD and LCOS, DLP have better motion resolution, lower 3D crosstalk, and overall image uniformity, but have low contrast ratios. Some may also notice the “rainbow effect” (around bright objects) in inexpensive DLP projetors. DLPs are also more expensive.

Projector prices: Between hundreds of dollars to thousands. You will notice the difference between $1,000  and  $3,000 projectors, but you will not probably notice taht much of a difference between a $3,000 and $30,000 projector.

The best projector in the market: Sony VPL-HW40ES / VPL-HW45ES Full HD 3D home theater projector. (best overall picture quality, is also quiet and can be fit in most rooms)
The second best projector: Epson Powerlite Home Cinema 5030 (slightly behind Sony on image quality, slightly)
The best projectors for occasional “big screen” sessions: There are many lower-priced options under $1,000, and some great projectors for under $500.