I am contemplating to get a mid zoom lens. These are the lens that I find that is suitable for my needs but would like comments from those that have used these lens before. Streetshooter and mpenza has given some pointers on the Tamron the more the merrier:

Sigma

28-200mm f/3.5-5.6 Compact Aspherical Hyperzoom Macro
28-200mm f/3.5-5.6 DL Aspherical Hyperzoom Macro

Tamron

AF28-200mm F/3.8-5.6 XR Aspherical (IF) Super Zoom

Canon

EF 28-135mm f/3.5-5.6 IS USM

Comments?