I think you will be fine with either unit. Now with the $200 rebate on the S3 and the fact that this box can be purchased for approximately $600 (before rebate), the final cost comes in around $400. Not bad, in fact, if I were in the market today for either box, I would purchase the S3 over the TiVo HD, the extra $100 gets you a better remote and more storage space, as well as a few other bells and whistles you probably don't need.
Both boxes, in my opinion, are viable and reliable. The TiVo HD had some issues when it was first released, but overall it has been a great unit and I have no regrets whatsoever.
Both boxes, in my opinion, are viable and reliable. The TiVo HD had some issues when it was first released, but overall it has been a great unit and I have no regrets whatsoever.