I have been using 3 HD20's for about a year now, as a home theater projector and for my gaming PC. I have found that it compares extremely well with units 3-5x its price, except for black levels. If you intend to use this primarily for dark images, you will need to be prepared to setup the viewing area so that there is absolutely minimal external light getting in. I also would recommend using a medium-light Gray projector screen, as it really does make the blacks look better without hurting the overall color accuracy.
I have used it for 3D gaming, with the 3 projectors all combining their image into one, and the results are nothing short of incredible. The brightness doesn't drop due to the 3D, and the resolution stays a full 1080p instead of being cut in half.
Also, if you are a gamer and are interested in running Nvidia Surround or AMD/ATI Eyefinity, I can promise you that you will never want to go back to 3x 1080p monitors again after using 3 projectors! No bezels, absolutely seamless transition, and if you are able/willing to have the 2 side screens at an angle, it is beyond "real" feeling. Sure, I would prefer to have 2560x1440/1600 resolution, but with projectors this is much less necessary than with large LCD Displays. I have a trio of Dell Ultrasharp U2711 that I use for my "traditional desktop" (same PC), and while the increased pixel area is insanely useful for productivity, I am hard pressed to find a significant difference between the two display types in gaming. Running a 3930K @ 4.6Ghz on a Rampage 4 Extreme with 32GB DDR3-2540 10-12-11-32, and with a grand total of 4 EVGA GTX680 4GB cards in Quad-SLI overcooked to 1380core/7840mem (CPU/MB/GPU'S all custom liquid cooled), I stillhave to turn the AA down when gaming on the3x U2711 displays, but when using the 3 HD20'S and playing Crysis 2 (DX11 Texture Pack), Skyrim (Extreme Texture Mods), or Metro2033, I am able to run at the absolute highest quality settings AND with 8x(or modded 16x) MSAA/TXAA (TXAA 2 enabled when possible), full Tessellation, 32x Anisotropic Filtering with Triple Buffering, and everything else (Full HDR, etc). With the Dell displays, I have to drop AA down a notch or two and same with AF, in order to maintain a minimum frame rate of >60fps, but with the projectors all these settings make the image quality so smooth that the difference in pixel count, 6.22mil (3x 1080p) versus 11.06mil (3x 1440p), is negligible.
I really can't recommend this projector enough! If you are fortunate enough to have a nice PC and the money to set up a multi-display setup, 3 HD20's with 90-120" screens is as close to virtual reality as you can get! Throw in a nice 11.2ch receiver with some good speakers (I use 2x Definitve Technology BP7000SC towers for Front L/R, 4x Mythos ST SuperTower's for Surround L/R and Surround Rear L/R, 2x CS-8080HD's for a dual-speaker Center Channel, 2x Mythos Gem XL for Front High R/L, 2x SR-8080BP's for Front Wide L/R, and 2x SuperCube Trinity dual-driver subwoofers; all powered by 3x McIntosh MC452 2x450W + 4x MC303 3x300W + 4x MC2KW 1x2000W Amplifiers, a pair of Processors (MX151 + MX120), MEN220 Room Correction Processor, 2x MPC1500 Power Control Systems (Voltage Regulation to less than 0.0005% fluctuation, Automatic Power Factor Correction, Surge Suppression), Furman IT-Reference 20i Line Conditioner/Surge Suppression/Isolation Transformer, and protected by an APC Symmetra 16kVA 12,500W UPS with quad-pass transformers.