Hell, my Knights weren't bad compared to my daemons, orks, or even TSons. Kinda sucks having to drop $80 at once for a box but hey, you only need like 12 models tops.
That's a very fair point about the initial investment versus the total model count needed for a playable force. Knights definitely offer a unique appeal on the battlefield for that reason.
Absolutely, it's a significant upfront cost, but the impact and presence of a fully painted Knight on the table are unparalleled. Plus, the reduced model count makes them a really manageable project for many.