Eric, I can assure you that what Tradeinn sells is regular first quality retail goods. I recently ordered a pair of Santini winter bibs and a Stronglight chainring, all arrived in it's retail packaging of course. Shipping was slower than the estimate, but I've ordered things from Europe before and that is typically the case. Anywhere from 2-4 weeks for non-premium shipping. Sometimes the orders are slow to process in the first place, to even be sent out for shipping. Other times it sits in the airport for days/weeks. US shippers have nothing to brag about though ! Customs can take awhile too. What's funny is if you buy premium shipping, it comes in days. Merlin Cycles orders certainly did, from the UK.
Retail goods from reputable retailers that sell for less in another market other than the US market doesn't mean you're getting anything less. Myself I only purchase overseas from well known/reputed retailers. Not everything costs less however, it's a case by case basis. Not everything is available either, with the geo fencing some retailers are forced to agree to, or they don't get to sell anything from that mfr.
With Tradeinn do note the shipping cost of larger/bulk/heavy items as the ship price can skyrocket quickly !