I've used them on and off for about the past 2.5 years and haven't had much hassle. Just be sure to use sellers with higher feedback. What I have found however with both DHGate and TradeTang is that in the event of a dispute that the c/s are very pro seller and will do all they can to limit loss to their own vendors.
However, on the odd occasion that I've raised disputes, I've stood my ground and handle the situation firmly which has resulted in an outcome that I've been happy with.
If you're looking at dropshipping high quality but unbranded electronics you could always try Chinavasion. They have a great range of stock and they usually ship within 24 hours with DHL, Fedex, TNT with tracking numbers etc - the delivery times are frightening fast (China - UK in 48 -72 hours). The only downside is that they do not actively 'zero rate' valuations for customs so there's always the duty element to be careful of. You CAN instruct them to mark as 'GIFT' and ask them to lower the value but in the event of loss, damage or confiscation, unless they've displayed the full price of the product there's not much they can do for you.
PS - I'd just like to point out that I'm not affiliated with Chinavasion.