I was on the gel for a bit when I ran out of injectable T. It should work.
<negativity>
Like others have said, it was messy and inconvenient and you have to use a surprisingly large amount of the gooey stuff to get the same effect as the injectable T. If you just wish to do this because you find the shots annoying and painful, I'd say it's likely that you'd find the gel even more annoying.
(It dries on your skin funny and feels crusty for awhile after you put it on, even if you rub it in really well. It's alcohol-based so it stings if you get it on any cuts or backne. It feels slimy on your hands until you wash it off. Maybe I'm just too much of a compulsive hand-washer for it and it might work for you if you're not.)
Having to take T every day also tends to have the effect of reminding me that I'm trans every day (and not in a good way), which I didn't like.
</negativity>
I'd rather have one shot every two weeks and get it over with, personally.
But, as with everything, don't take other people's words for it; I recommend trying it yourself and seeing how it goes.