I'd recommend not skimping when purchasing an important tool like a torque wrench. I've always used/bought either Mac, Snap-On, or Matco....torque wrenches. The reason I buy these and pay quite a bit more, is for the fact that I can go to the tool truck and they can calibrate the torque wrench or send it in to be calibrated. If you use this wrench alot I'd do this about once every 6-8 months. It really depends on how often you use it....and what you use it for.
If you torque alot of highly critical components....like...main bearings, rod bearings, head bolts, lug nuts on expensive wheels and other expensive drivetrain-related items, I think it's worth the extra money to get a torque wrench that's certified accurate and can be checked, re-calibrated and re-certified periodically.
If it's for other components that aren't as expensive or critical like bracket bolts, or other fasteners...then maybe the cheaper torque wrenches would be the way to go for that usage. I have torque wrenches in inch/lbs and in ft/lbs configurations. I also like to have them in 1/4", 3/8" and 1/2" drives as well, because sometimes you just can't fit certain drives in certain areas.
Aron