If you can handle needles at all, just go the injection. It's the cheapest (by far), the quickest, and the least irritating to live with on a daily basis.
I get a nurse to do mine (cannot DIY where I am) and it's not really all that painful - can get a bit stiff and a little bruise for a day or two. There's very little in the way of nerves at the recommended injection site.
edit : For the record, bi-weekly Sustanon 100 is what I'm on.
I personally haven't used gels - but as far as I know it's a twice a day application (and subsequent 10 - 20 mins drying time), and the risk of contaminating others if you make too much skin to skin contact (rare from what I hear, but possible).
But on the bright side, there's no needles. I think the gels are more common with people just starting T (due to their short time in the body - you can adjust levels, or even "abort mission!" with quicker results), and also with people with needle phobias in areas where self injecting is the norm.
Someone with a preference for gels over injections would give you a different opinion on what they are like to live with. I am biased towards injection.
I personally haven't heard of people on the patch, implant, or using the cream as a primary delivery method.
As far as your body can tell - T is T is T. In the end, it really doesn't matter how you get it. It matters that you have T levels consistantly within the male range (if that is what you are going for - I am assuming FTM here).
Go for the method that will disrupt your life the least, and is the best for your budget.
