I can speak to my recent experience with Tiger Japanese. I picked up one of the W10 Avenir engines they have (had?) on sale. They also had the free liftgate delivery option for residential delivery at the time, so I ended up paying $734, plus $135 shipping (Canadian) to my front door. Despite trying to correct their error with my shipping address three times, I had to resort to talking with the shipping companies, both for the engine, and the replacement turbo (more on that in a minute), in order to get my shipping info corrected.
The engine itself arrived strapped securely to a wooden pallet with a cardboard pad underneath, with the usual crushed fuel rail, minor oil pan dings, intake piping missing (including BOV and boost solenoid), hoses and harnesses cut (expected), and a seized turbo. I contacted them right away about the turbo, and ended up sending the turbo to them, and they sent me a replacement in reasonable condition. I ended up talking with one of their CSRs named Mike, and we chatted for a bit (apparently they are looking at a move, or branching out, to somewhere out here near Vancouver).
I consider myself a reasonably bright individual, so why would I take a possibly unreasonable gamble on this engine? This was not, in my opinion, as big a gamble as one might think;
1. I chose a W10 because ~90-95% of the parts are USDM interchangeable
2. The interchangeability meant most parts would be cheap and plentiful
3. I am not a drop-in-and-go engine swap guy;
The DET is still on the stand (It was delivered six weeks ago), and in my spare time I have been systematically freshening the seals, sensors, checking bearings, cleaning the light-moderate oil varnish, media blasting and repainting where appropriate, etc. I am building a 300+ WHP SCCA SMF machine to kick some SRT-4 ass in the Pacific Northwest region, and I knew I was going to tear into the engine anyway. The turbo condition didn't bother me, because I was planning a GT28 upgrade anyway. I have BC Stg2 cams to drop in, so cam scoring (if present) wasn't a deterrent. I had to replace my roasted high-comp engine, so I decided to take the plunge.
Did I take a gamble? Sure, but I was fully informed walking into it, and my expectations/goals mitigated the risks. Would I do this on a less-common engine? Honestly, not sure I would.
Darrin