Looking at buying a late 2011 Macbook Pro 15inch i7 2.9ghz , 8gb ram,750 GB hard drive. This is from a local seller for $400. Sounds like this is a crazy good deal. Thoughts? Also how would this machine do with Yosemite? How many years would those specs last?
That is a fair price. But as already stated, as long as everything is working and it is in good condition.
Well, the "classic" 13" MacBook Pro is still available, hasn't changed much since late 2011 (I think it had a minor processor bump) and costs about $1300 new for the i7/4GB/1TB config, so make your own judgement. Not such a good deal as the 8GB/15" would have been though, and if the seller initially told you that's what it was, walk away! These were the last MacBooks with user-upgradeable hard drive and memory, so you can easily add third-party RAM and a SSD (recommended) which is good. You can also swap out the DVD drive for a second hard drive, so you can have a fast SSD as your system disc and a big HD for storing bulky data. Screen is nothing to write home about, and actually slightly lower res than the 13" Macbook Air but perfectly OK. Main downsides: only USB 2.0 (no USB 3), and only a single Thunderbolt port which is also your only way of connecting an external display: this can limit the usefulness of cheaper Thunderbolt disc drives etc. that don't have a through connector (not so bad if you don't need an external display).
$400 is an ok deal for it especially when clueless buyers are paying that much or more for 2009 models on ebay. As long as it checks out ok, go for it.
The 2011 15" models had a lot of problems, but their market value is still probably at least that much. This is not a 15" though. There was no 2.9 ghz 15". Only the dual core models were clocked that high, which means it's a 13". That's slightly misleading, because it ignores that the 13" cmbp still had a better display. The resolution difference is negligible. In my opinion the difference in viewing angles is not.