[Android Head-Units] sciallo:
I don't know that there is such thing as a "reputable" seller. I wouldn't know where to start helping you find one...

I do however wanna help, and I prought some of these points up before...

1 Buy somewhere where there is some sort of customer protection, according to some ebay is better than aliexpress alibaba and the like. I haven't tried anything but ebay, but just out of convenience: what I wanted was there... The way I understand it (and I'd love for someone who has real experience to confirm) those sites are not only providing a sales platform for the various sellers, they also provide escrow service. When you pay, they hold the money until you receive your product and are satisfied. I remember a while back someone purchased a unit on a whim without asking a single question to the seller about it until after he paid, then asked a question, turned outthe unit was not even available anymore. Seller never got the money, he got reinbursed by alibaba... (sorry, I'm to lazy right now to go look for the posting in I don't even remember what thread)

2 As said above, there are different sellers on those sites, just like ebay and amazon... They treasure their ratings and accounts with those sites as it enables them to sell more. Choose a seller that has some good amount of ratings, one that would have something to loose in case of a dispute resulting in negative feedback

3 Pay by credit card or paypal... all else fails you reverse charges, it might become a somewhat lengthy process but the tendency is to refund customers and dispute between sellers and credit card companies at that point.

4 READ their posting, return policies and all other "promises". Those will be met or you have a right to start a dispute. You will note that in all cases with these chinese sellers you would be responsible for shipping the unit back. From my personal experience that is a 70-80 dollar deal. I said in an earlier post, you're not gambling 500 dollars, you're putting a $500 deposit on a $80 gamble...

5 In the case of a unit you know you'll want to keep if it works this wouldn't be an issue but (maybe... see #6), since you MIGHT want to return it for a refund you are better off finding a unit that has a "shipping included" price or ask the seller what the policy is in case of refund... In most cases they will refund you the price of the unit and you pay to ship it back (but you also don't get a refund on their original shipping price) that is why you'll find so many small items on ebay selling for $1 +$10 shipping, they avoid returns that way... (though some ebay policy might have changed on that as it seems like a M.O. of the past). So, if you find one seller that wants $400 + $40 shipping and one that wants $450 shipping included, you might be better off with the second seller depending on the first seller's policy...

6 As soon as you receive the unit put it to the test, I would hook up a couple of speakers to it, a 12v. power supply from an old computer or whatever you have and set it up on the desk. Make sure it works, back up everything that is in the SD card, take pictures of versions in the menu->about device and mess with it heavily, see that it does what it promises to do the first day you have it. If anything is defective you could return it for exchange, but you might be better off returning it for refund for 2 reasons:

6a: If your finances allow you can buy the next one while your return is going back. You will want to ship it back the most economical way possible with USPS (TRUST ME on that!) and it will be two weeks before they get it and issue the order for a new one to be sent to you.

6b: (another personal experience) you get a whole new return policy started on the new unit, new order, new transaction date, new credit card transaction... you get the idea...

7 Ask some questions before you buy it, it will give you an idea of who you're dealing with. Let me give you a little heads up though, it will be a chinese individual going by some "Linda" or "John" name, he/she is simply sales, in most cases these sellers handle anything from Jewelery to motorcycle covers, clothing to electronics. They might know just enough about these units to try to sell them and there is a language/culture barrier in communicating with them, it's ok as long as you understand it. Don't expect much customer support from them or even from the manufacturer for that matter, if there is a problem they try to help as best as they can, they try to provide files if files are needed (TRY is keyword, I was given a downgrade at the time of my first exchange - OUKU - when I was asking for an upgrade). Given the track record of support and firmware releases of chinese companies, one of the things I would strongly try to negotiate as part of the deal, is that they send you a link or a copy on the sdCard of the complete firmware and MCU update as installed on the unit so you can restore the unit without having to spend days emailing the seller who will email the manufacturer who will email the engineer.... (also in my experience communication is also painful due to jet-lag, I rarely was able to exchange more than 1 or 2 emails a day at the most. they sleep when we're awake).

The firmware would also be a good thing for us all to see, hopefully it's not encrypted like the AN-21's and we can do "things" with it :)

I hope this helps...