We sure do love Twitter apps and even though Mango goes a long way for most people, there are those who still want a dedicated client with more features on board.
TweeterLight isn't exactly new, heck it just hit v1.4, but it's one we missed when it came out. Turns out it's a pretty solid client. As you can tell by its name, it is meant to be light and fast, so if you're looking for a Swiss Army knife of functions, this isn't for you. Then again, it does have a nice feature set and the speed make up for it for many of us.
It does support Read It Later, uploading of pics, geolocaton, contact look up (using a list picker) and trends. Plus with v1.4, it is now Mango ready. It also highlights new, unread Tweets, making management a bit easier.
Overall we dig TweeterLight a lot--it's fast, supports full landscape mode and has a nice UI. Sure a Live Tile wouldn't hurt but for $0.99 with a free trial, it is certainly worthy of consideration if speed is your concern.
Pick up TweeterLight here in the Marketplace.