Hi, and welcome to the site!
The Ascaso I2 is a great little grinder for the money, however stocks are thin on the ground at the moment. I have been told to expect ascaso conicals back in stock in about a month ... which probably means six weeks ;P If you can find one, snap it up.
The Compak K3 Elite looks very promising, with stepless grind adjustment and what seems to be quite high quality construction. We have been keeping our eye on it for quite some time and hope to make a decision on stocking it this week. I think that Chris from Talk Coffee currently has them in stock.
I owned a Rocky for a few years and, personally, found the stepped adjustment to be too limiting. Others have reported that they dont find it a problem. You will have to make your own decision on that.
Whilst the machines in this class are different, I dont think that you would get much bang for your buck by selling your gaggia to move to another machine. Getting a good quality grinder will probably help more. The one thing that might be worth looking into is getting a rancilio silvia steam wand to retrofit to your machine. (Note that this is a modification that I have never performed, only seen reported, so you should take care to inform yourself of the possible risks, if any.)
I hope that helps,