Sprayskirts seem to work better and are less intrusive for most people.
The dodger does protect your legs and lower body almost completely, but not the upper body and face. It also does shade your legs from the sun, that a Sprayskirt can't.
A Sprayskirt keeps most spray and splashes off all of you, especially the buckets in the face and chest when heavy sailing. A Sprayskirt will slow you down if your boat submarines (less common in a TI), but unless you are going long distances or racing, it's a good thing, as it stops the dive. A minor adjustment to your course (sail ~45 degree into the waves) should stop most dives.
You can sew your own Sprayskirt from a free pattern (AI) on my website (for TI, just cut it 4 inches shorter), or other prototype designs here on the forum. You can also buy just the sewn material to rig your own, or a complete kit from my wife Dee (links from my website) and a few Hobie dealers.
Enjoy!