I use Pavtube for coverting TiVo videos for my iPad. It works very well and I haven't really had any problems. Conversion speed seems fine and the videos look good on the iPad. I saw Pavtube mentioned in the TiVo forums as a good way to convert for the iPad so I decided to try it. It's much better than TiVo's converter. TiVo's converters for mobile devices are terrible.
Follow the optimal settings to get excellent playback quality.
Video Codec: H.264 Size: 1280*720 or 768*576 BitRate: 4000kbps FrameRate: 30.00fps
Audio:Codec: AAC SamplerRate: 48000hz BitRate: 128000bps Channel: 2
How to turn TiVo shows into iPad HD videos with iPad Converter?