The only Venator kits I know of are both currently out of production. There is the Revell 1/2256 one and a jpg 1/4222 one.
Although, the Revell kit may be seeing a new release at some point in the future. Some of us have been writing them asking for a reissue and they seem to be saying ti will happen
As far as the best kits, Bandai and Fine Molds. Bandai's generally winning out in accuracy, but Fine Molds sometimes has better scaled panel lines and better decals.
Revell kits are the next best. Often they are the only kits available for those odd subjects and cover a lot that no other company has done, or fill in scales no one else has done. Generally these kits need some tweaking to get them to Bandai or Fine Molds level detail
Then there are the long out of production MPC/AMT/ERTL kits. Generally these have all been surpassed by newer kits from the companies above, but there are a few that have yet to be done, or at least done in a reasonable scale (like the B-Wing, ATT, Bongo Sub etc...)
Then there is the whole "free-for-all" if you will of garage kit makers. These are often small, or limited runs, but often are done studio scale, or cover subjects that no company has done in styrene
- - - Updated - - -
oh, and still a work in progress, and some of the info on there is not complete, kept up to date, or is 100% accurate, but nonetheless, it is still a good place to start
http://www.keeperoftheforce.com/viewtopic.php?f=3&t=1363