One thing to consider when picking any bait to flip is Fall Rate of the bait and depth. In cold water it is important to have a slow fall rate to keep your bait in the strike zone longer.

Adjust your Jig and Tx rig weights to account for the water temp and thickness of cover. Thin Profile Jigs fall faster than bulky jigs... Thin Worms fall faster than bulky Creature/ Craw baits..etc. You have to have enough weight to get thru cover and if it's windy you have to have enough weight to keep good contact/ feel with your bait.

One overlooked bait for flipping is a Jig head with a soft plastic body. I like to use a creature bait with a stand-up jig head in cold water. I like a Chompers skirted twintail grub on a 5/6oz stand-up jig head. It has a lot of action and bulk for a slow fall rate that gives you the best of both baits in one package.

Bazz

The ONLY time I'll flip plastic baits is if they just won't eat the jig. Even then I spend most of the time trying to force the jig!
In my experience the better fish will almost always opt for a jig over just a plastic. I often feel like flipping a texas rig is giving up on the "big bite".
Now, there are exceptions to every rule... but on my lakes these have been my experiences.