As far as custom launchers go, Sense is pretty good. It's certainly better than Motoblur or Touchwiz, in my opinion. Still, it can use updates from time to time, as new versions arrive with new features.
You may be wondering how you receive those updates. The answer is that you should already have them, if they are available. Why? Because Sense UI updates are usually pushed as OTA updates. That is to say, they should automatically be downloaded to your phone and installed, just as an update to the Android OS is automatically downloaded and installed.
If you own a Desire HD, Desire S, Desire Z, Incredible S, Inspire 4G, S710d or S710e you can do an HTC Sense UI update via the HTC Sense beta website. This website is supposed to become a hub from which users can obtain a variety of information about, and updates to, Sense, but for now it supports this very limited selection of devices, and really doesn't have many special offers.