The Ruger PC Carbine in 9mm using a Red Dot can be a lot of fun at USPSA Matches. Here is a good shooter taking full advantage of the Ruger PC Carbine.
Dot was a budget (~ $70) Tasco (30MM) PCC Red Dot. Not super bright, but it works. I would much rather have a Holosun Green Dot (510) but the cost is over $250.