Not familiar with your particular examples, but there is very little difference among chinese engines from the experience I have had.
I buy all mine from ebay for $150 simply becasue I see no reason to pay extra for a website or a riveted numberplate.
Your results may vary, but I'd suggest going with a vendor you feel good about in case you need service after the sale.
I've been very happy with my ebay vendor over the course of my building 25 kits or so....