Until recently I'd not heard of TP-Link. When I finally did notice them, the styling, price point and some reviews of their kit made them seem cheap and nasty.
Well, I am here to refute that view! The TD-8840T is in their "newer" style which, while not exactly pretty, is perfectly acceptable (and a lot better than the retro black curvy style I refer to above). It was easy to set up with the built-in wizard (no, I didn't use the CD setup tool), doesn't get at all hot in operation (it's rated at 6 Watts max.), hasn't crashed or glitched on me once, and seems to hold the ADSL sync well. Besides the normal firewall and filtering settings, it has a fairly extensive array of features (such as SNMP, QoS, VLAN, CWMP) that most people will probably never use. The web configuration interface isn't elegant, but it gets the job done and is no worse than many others. My one gripe is that the system log facilitiy is short, cryptic and generally useless.
I bought this router to replace one of another make that was unreliable, and represents the sixth different make of router I've owned. Based on the performance of this device, I would not hesitate to buy another TP-Link product. I use it in conjunction with a much flashier (and much more expensive!) wireless device, but I like the TP-Link because this is the sort of kit you can configure once then forget about it, while it sits quietly doing its job.