I'm on a T cream that I apply every day. I've only been on it for about five weeks, so I can't comment on the long term changes, but I've had some changes that are comparable to other that have been on T for the same time--my muscles have grown, my voices sound scratchy a lot and cracks. Maybe I would have more changes if I did injections, but like you said, everyone reacts differently.
I don't know about the gel, but the cream isn't messy at all and doesn't smell weird or anything. It only takes me a minute or two to put on, whereas I can imagine the injections turning into a 45 minute anxiety battle with myself. It was pretty cheap as well, about $20 for a two month supply from a compounding pharmacy.
If you want to try topical T, I'd say go for it. If you're not happy after a couple of months, you can always switch to injections.