Right Angle View Finder

Does anybody have any experience with right angle view finders for Canon DSLR that can give me some advice? I often find myself in situations where it seems one would be useful... typically when my camera and tripod are close to the ground. My two questions are (1) are they easy to put on and take off, and (2) should I buy a brand-new Canon model for $180 or a $40-$50 third-party brand off eBay?
Thanks!

John, I own Canon's model and have to say it is very useful in those low to the ground situations. I'll have mine at the Spring Gathering so if you want to give it a try before you buy let me know. I use it sparingly but when I need it the thing sure comes in handy. It goes on and off easily and I like the magnification factor too.

Don't know anything about the off brands. Hope that helps.

John, I'm a Nikon shooter and use a right angle finer a lot when shooting my floral macros.
I know it is more expensive, but, accessories made by a manufacturer for specific models work better than 3rd-party units. I know this with Nikon from my own exerience and from what other Nikonians have told me.

John, I use a right angle finder for low angle shooting and macro work. I am a Nikon shooter, and after much thought, I got the Hoodman. I really like it. I can't speak for other third party brands, but the Hoodman is well made and fits the camera perfectly; it comes with several eyepiece adapters. It is not, however, $40-$50, (about $120 retail at Adorama) so it may be more fair to compare it to the Nikon and Canon versions. I also bought the Hoodman with the thought that I may shoot Canon someday. One less thing to replace.

John,

The Canon model works good but since it just snaps on you have to be gentle with it. It comes with adapters for the two major eyepieces.

I am selling ALL my Canon gear so one of those will be on eBay in the next day or two.

Thanks everybody.