It depends on what you want to do, I mean yes, there are limits, but things like Dark Basic are still incredibly flexible.
Everything I've seen you produce in Visual Studio can be done in Dark Basic Pro, granted you'd need a GUI plugin, but there's a lot of plugins out there that extend the usefulness of DBP. In AppGameKit, creating an interface isn't that difficult, because you have commands for creating the interface, just like you do in Visual Basic, except this interface can be clicked on, but it also can be pushed on a touch screen. Though you don't get a GUI editor like you do in Visual Basic, unless of course one has been coded since I last played with it, which is possible.
If you've got a copy of Dark Basic Pro and are concerned about whether AppGameKit is worth the money, start playing with it. I'll give my examples in DBP as I use it and I want to encourage you to give it a go, as you sound interested. Yes, it has bugs, but so does everybody program and over the years it has become rather polished.
Whilst it is simpler to use, but I wouldn't say it's that limited. For examples of what has been done in DBP - FPS Creator was programmed in Dark Basic Pro, the
Star Wraith video game series was created in it,
this map editor was coded in DBP without the use of Dark Lights, for graphical capabilities check out
this video (it's a landscape editor, but look at the light effects achieved),
here is a MIDI creator somebody made check out the Work In Progress and Program Announcement sections to see what members here are doing with it. Obviously we can't show you everything it can do, because if we could, then it would be too limited, but hopefully those examples should show you what people are doing with it. Also, check out the AppGameKit section to see what people are doing there.
Of course to achieve the greater results you need to know what you're doing and to be realistic about what you can achieve, but then it's exactly same is for C++ and VB. As far as I've seen, for me at least, jumping to C++ of Visual Basic is less preferable and yes, I've tried it, it's just too much work to get it to do the same thing, yes there are advantages, but I don't see me using them.
However, what is it you want out of a program? I think that's the most important question to ask, because then we'd be able to tell you if AppGameKit or DBP is suited to what you want. Based on your previous creations, DBP will work and AppGameKit could be used to create the mobile friendly equivalent (obviously with a more suitable GUI).
How about this for a challenge? Open up your copy of Dark Basic Pro and try to learn to make a simple game in it or download the trial of the App Game Kit and do the same. I think the best way to evaluate a product is to try it. Perhaps see if you can recreate your Ant Farm game, just don't use the GUI plugin for DBP, generally using 'forms' like in Visual Basic or the Windows GUI in a game can make it look tacky and the GUI plugin is design more for applications than games.
If you want help or advice using DBP or AppGameKit, then obvious their respective forums will be perfect for helping your learn them and quickly. At least I've always found this forum to be fantastic at helping fix or improve code.