DLNA performance is largely going to depend on the quality of your network connection, the performance of the NAS & the server software providing DLNA.
I would think your best bet would be to just buy one online & test it thoroughly within the 7 days allowed by DSR & simply return it if you don't like it. All it will cost you is the return shipping. Just don't go removing any labels, tags or anything else that would distinguish it from new. Also make sure you choose a retailer who is happy to abide by the full terms of DSR & not impose their own (essentially illegal) terms.
I would think your best bet would be to just buy one online & test it thoroughly within the 7 days allowed by DSR & simply return it if you don't like it. All it will cost you is the return shipping. Just don't go removing any labels, tags or anything else that would distinguish it from new. Also make sure you choose a retailer who is happy to abide by the full terms of DSR & not impose their own (essentially illegal) terms.