It'll be helpful for discussion if you tell us what computer you have.
But generally, my advice is, if you have an Intel Mac get the hybrid, if you have a PowerPC, get the 250.
I think the general consensus is that if you're just interested in using the thing as a tv tuner/tivo, then the hybrid will do the job just fine. I have it hooked up to my cable after the main line splits to go to my high speed modem. There has been no loss of speed etc. because of the split. I have not hooked up an aerial to try out HD.
The 250 is good if you have a lot of analog tapes that you want to convert to digital and need something dedicated to the cause. I think that the hybrid would be perfect for your needs. I have the same iMac as you.
Mick
Can someone tell me which is best to purchase the hybrid or the 250
are there any major differences other than one uses the resources of the mac vs self powering?
Just be aware that a lot of digital/HD content _is_ encrypted, and as such, the eyeTV will not decode that. You should be able to get anything that isn't encrypted. Nobody knows what will happen next year when digital is the standard and not an option, but for now... much is encrypted. I can get networks and a few other HDs, some digitals. If/when I switch to DTV that should be interesting because then I assume it's coming out of the box which is a decoder of sorts.