When I bought my 7d a couple of years ago, I also got the Zacuto z finder. My niece is in school and is reay to buy a 7d, and asked me about viewfinders. She really doesn't have the money for the Zacuto after everything else, and I was wondering what else was available. She weras contacts so I guess she needs something with a diopter for adjusting.
Any suggestions?
Bruce Yarock

I have been using the Hoodman version for a while now and its pretty good. Not great, but it works.

The Hoodman works fine with the 3X magnifier. Otherwise it's too picky about having the eye centered. Redrock has a simple mount that is a bit of a bother to mount/remove, but it's solid. The Hoodcrane works too, but is a bit Rube Goldberg.

These cheap Chinese made loupes are great. They are available under several names e.g. GGS, Perfect & NEEWER amongst others. I have had the opportunity of directly comparing a Zacuto Z-Finder & one of these while shooting with a colleague & we both agreed that there was little or any difference in optical quality. It's not up to the Zacuto build quality but it does the job very well & is only about $40. Amazon.com: NEEWER HD DSLR LCD Foldable Viewfinder with 3.0x Magnification: Electronics

I didn't care for how the Letus was hard to remove. In case this helps....this thread links to a review...
http://www.dvinfo.net/forum/canon-eos-5d-mk-ii-hd/481189-dslr-viewfinder-review-comparison.html

I had the Loupeman, and optically it is no good. Only sharp in the middle, and I found it worthless as a focusing aid. Better go for the Zacuto, it's worth it's price, and if she cannot afford it, look out for a second hand one.

I had the Loupeman, and optically it is no good. Only sharp in the middle...

True. The basic Hoodman Loupe is way too soft in the corners. However, if you add the 3x magnifier it's quite good. No, it's not Zacuto good, but it's a fraction of the price.

If anybody here has the Hoodman Loupe, I strongly recommend the 3x magnifier. It transforms the loupe from frustrating to competent.

I've been using the LCDVF for the past 2 years on all my DSLRs. It's cheap, simple and effective. I'd highly recommend it.

The LCDVF has no diopter. The OP said a diopter was needed.