Recently got my original Rival RMA'd. That one worked without any flaws at all. The only issue was the rubber grips. The location where the thumb was almost completely gone (closest to the hand) with the plastic mold of the mouse visible over 1.5cm x 1cm, and there was developing (nearly to the base plastic mold of the mouse as wel) where my other digits were on the right side grips. Steelseries OK'd an RMA (despite being over 1 year, it was something like 14 months purchase, but give them a ticket and let them decide if the RMA is able to go ahead or not if you have said issue).
Anyway, the information I wanted to add was, I was given a code to use and I re-ordered the Rival equivalent and that's the Rival 300, and on arrival, encountered some stuck mouse button issues (mouse button was released but the mouse appeared to keep it down and signalling anyway). This required a firmware update that can be applied via their Steelseries engine software if you run into this issue.
Otherwise, I purchased the Rival (and now Rival 300) on recommendation that it was close enough to the classic MS Optical Explorer 3.0. And works really well overall.
