It's like any consumer brand, there are good models and bad models. The more you pay the better the router you'll get. most Dlink SoHo stuff is fairly uninspiring average stuff. Like anything if you make the leap from SoHo to proper business grade kit the performance jump is noticable. As is the price.
It also depends what you use it for. At the highger end of the consumer market some routers are better for features and managament others for throughput.
Eg. Cisco 877 is great for ADSL and has tonnes of cleverness, but it'd struggle to route LAN to WAN at 50mbit, making it less appealing to big downloaders.