Last review on Tom's Hardware of the high-speed wireless hardware (802.11g) had Linksys providing high speeds but less reliable connections, and D-Link providing the reliablity but not quite matching for speed.
Each has their slight security flaws, each with their own workarounds or fixes (for more specific info on these, see the Bugtraq archives).
edit: I was thinking of Linksys vs. Netgear, not D-Link, in the above comparison.