Vivitar and Polaroid extension tubes

I am interested in getting a set of extension tubes to use with my 40D & 100 f/2.8L macro lens. I was originally going to the get Kenko, but Vivitar and Polaroid also make tubes sets for less than half the price. Does anyone have experience with those tubes? -rick

I have a cheaper set with contacts ($80). They are all metal and work just fine. I see no reason to 'upgrade' to the Kenko tubes.

There are some that may have plastic release levers that could be prone to breaking of you are rough with them, but I've not heard of anyone having a problem.

Mine do allow a bit of rotational give, not excessive but noticeable, but I don't see that as a problem (may of my lenses also rotate 1/2 mm or so in the mount).

Update. I bought a BNIB Kenko Extension tubes from a guy on Craigslist for $100. I'm a happy camper. -rick

I have the Polaroid set, and with the Tamron 90 it is a great setup. The tubes seem solid and have not been an issue as yet.

I have some cheap tubes, I think polaroid. They were 10 bucks. They work good with my kit lens but when I attached my reversed pentax 28mm to the front I got a reflection within the lens. Not sure if it was the tubes or because the lens is only coated for glare on one side.

Just got my Vivatar tubes last night. Tight fit, but everything works as well as the set of Kenko tubes I owned years ago, and spent almost twice as much for. Looking forward to taking some shots with them soon.