I agree with Jolt on this one. There is a reason why everyone does the front crawl in freestyle events - it is just faster (you can do any of the main 4 strokes in a freestyle event). Some people are more suited to other strokes (I was a backstroker through jr high & high school), but typically they will still be faster with the f.c. Also, some people will be faster at one of the other strokes, but probably only if they primarily work on that stroke. Maybe you could time yourself at a given distance, once with one stroke and once with the other, and see just what the difference is for you, rather than comparing yourself to other people. If tris are your focus, and you don't have the time to put into extra swimming (I sure know I don't!), then maybe focussing on freestyle (crawl) would help.

How do people find the time, anyway? I find myself swimming once a week, and then mostly biking, or mostly running, or getting sidetracked by my mountain bike, or my job, ...