DLP as with any fixed pixel display will look perfectly sharp with a computer hooked up to it as long as you are running the EXACT resolution of the display.
Like, if you have a LCD monitor for your computer that is 1280x1024 - change your video to 1024x768 and you will see the image look really bad. Likewise, if your DLP is 1280x720, then run 1280x720 to it or it will look really bad.
Anyway - read the topic about CRT vs. LCD vs. DLP projection systems. Completely - yes completely - disregard any comments about DLP having moving parts as the micro-mirrors inside a DLP are based on semiconductor technology that is rated at about 20 years... or longer than most of the electronics inside most TVs will last anyway.
Bulbs are important to consider.
Video quality is important to consider.
Brightness is important to consider.
Viewing angle, continued maitenance costs, depth, connectivity, initial price, and size all are factors that DLP vs. CRT buyers should consider. There are pros and cons to both and the decision - in the end - is yours.