Picked up the R-200. $83 out of pocket, so much more palatable than $300.
I may actually go the premade route now; but only because my LFS needs a bunch of leopard geckos (and I have a surplus), so my out of pocket will be ~$75 for the E-shoppes R-100.
If not for that, I'd be making a DIY for sure, it actually looks like a fun project.
I have the R-200 for my 65 gallon tank and works very good using the Triton Method. Only issue is the rear return area which is hard to get to, small and limits the size of the return pump.