I've already recommended this site to friends. It has substantially the same benefits as other 100% cashback sites (except you also get shares in the company, which may or may not prove valuable in the long term) along with excellent customer service and good discussion boards.
In fact, if interested in joining, you could do me a small favour by using my referral link http://www.imutual.co.uk/?ref=2671.
Having used cashback sites for many years, I love the idea of being given shares in the company. If the company ever gets bought, that could be a nice little earner in addition to cashback. If not, I've lost nothing!
The forums are lively and most importantly, they seem to be more reliable in actually tracking and paying cashback than any other sites I have used. Top marks from me :)
This cashback site even gives and awards you shares in the company - it has a friendly forum where alerts and queries are promptly addressed. Rewards & cashback are reasonable and payments are promptly made. Well worth using.