If you’re going to get a box to work with Comcast then you have three options – the Series2DT, the Series3, and the TiVo HD.

The Series3 and TiVo HD both allow you to record from antenna or cable – analog or digital. They have dual-tuners and can record any two programs at once. And can record high-definition. You use CableCARDs with these units for digital cable.

The Series2DT does not do high-definition and cannot use antenna, and while it is ‘dual-tuner’ it is kind of a hybrid. It has dual analog cable tuners internally, so it can record any two analog cable channels (usually channels 1-99 are analog, even on ‘digital cable’), and you can have a cable box connected to the AV input for a digital channel. So it can record two analog channels at a time, or one analog and one digital channel (from the box). But it cannot do two digital channels at a time.

Of course, the differing capabilities mean difference costs – right now you can get a S2DT *free*, while the TiVo HD is around $250 and the S3 is around $350. See the current deals.

Refurbished or not doesn’t really matter – but with a new S2DT being available free, there is no reason to get a refurbished S2/S2DT. Get the free new box if that’s the unit you select.

All of the TiVo’s provide a good picture. The S3 & HD obviously do HD which is the best. But for standard definition they’re all good. TiVo gives you four recording quality options, so you can select the level you prefer – lower quality means more recording time, higher quality means lower recording time. You didn’t have that on the DirecTiVo because DTV is all digital, so the signal was always saved ‘as-is’. But with analog signals the TiVo encodes it locally. (The S3 & HD record digital cable channels ‘as-is’, just like the DirecTiVo did.)

Response time is pretty good, IMHO. There is some delay with the S2DT when tuning a digital channels because the TiVo needs to relay the signal to the cable box and wait for it to tune. But if you watch mostly recordings you won’t notice it. I just wouldn’t try to channel surf – but why do that with a TiVo?

If you go wireless, be sure to use the TiVo-branded wireless adapter. It works perfectly in my experience. I currently have two Series2 TiVos using them in my home, and I used to have my Series3 using one – but I ended up running wired Ethernet to handle my PS3 and Slingbox, so I connected the S3 to the same cabling. They’ve always worked great for me. The only trouble I had was due to a failing router, hardly TiVo’s fault.

If you have HDTV, or plan to get HDTV in the next year or two, you might take a good look at the TiVo HD or the Series3 since they have the most capabilities and are more future-proof, with HD support. But if you’re just going to use it with analog cable and/or only standard definition for the foreseeable future, then the free Series2DT deal is probably your best option.

Remember you have 30 days to return it for your money back if you decide you don’t like it. But if you liked the DirecTiVo, I think you’ll love using one with cable. You get the features you had on DirecTV – but a hell of a lot more since DirecTV disabled so many features. Like TiVoToGo, music and photos, Amazon Unbox, TiVoCast, etc.