744T is a nice all-in-one recorder that goes for around $3200 used. Keep in mind that it only has two preamps with phantom though, the other set of XLR inputs don't. The 788T has four preamps with phantom and four additional channels without a pre and costs about $6000 new with a HDD and $6500 with a SSD. They rarely come up used. I think if you get one of these you won't need to upgrade for a long time, which is why I plan on getting at least a 744T at some point.
No, that is not quite correct. The 788T has 8 inputs that can be mic, line, or digital. All 8 inputs are the same except inputs 1-4 use XLR connectors and inputs 5-8 use TA3 connectors to save space. (Other than having to make some XLR to TA3 adaptors, I have no issue with the TA3 inputs.) All inputs have phantom power which can be used for either mic or line.
I bought my 788T before the SSD option was available. I've never had a problem with my HDD unit, but I'd recommend buying the SSD version since it has a 256 gig SSD (vs 160 gig in the HDD version) and it's a SSD with a MTBF of 1,000,000+ hours.
The 788T is a very fine recorder: nice preamps, phantom power done right, excellent A/D, great meters, extremely reliable, redundant media and power, versatile, built by a Cheesehead company with excellent customer service, etc, etc, etc. Its biggest drawback is its versatility; it can be a bit complicated to operate, much more so than a 702. John Willett has called it "a bit fiddly", and I cannot disagree with that assessment.
Yes, it is more expensive than a R44, but it is less than a Cantar X2. You pays your money and you takes your choice.