I've been doing eBay shopping since 1998.
And if there is ONE thing I've learned, is that the lower you bid, the slower it ships. Doesn't matter if the two promises the same shipping times.
Also, the cheaper you go - the lower quality you'll get at the exact same product range. Because a lot of them will ship the lowest bidders the shittiest quality of the batch (kind of logical, don't ya think?).
And a above 90% seller success rate sounds nice, right? Wrong! You'd be amazed how many problems you'll have with sellers under 96% even at 97% good feedback. The trick is to look at their negative feedback, or / and their neutral feedback and see what happens for each individual product. The product is important here, because the same seller could earn a 100% feedback reputation on selling socks, but sell shoddy factory rejected production Arduinos with a feedback of 20% and less - and still earn a pretty penny. Many of the Chinese sellers just sells these by the thousands because it sells - they have NO clue what they're actually selling besides fake shoe brands etc.
The thing you need to watch out for - is the sellers that will tell you "please wait 40+ days because of your customs" etc... You know as well as I do that your customs don't give a hoot about your 2 dollar arduino, so if it takes 40+ days, and the seller says, please be patient, it's because the nickel-and-dime croock only wants to hoist good feedback while your complaint expires. Never accept this. Complain immediately. Down the bad sellers now, do not delay!