We all know and love the VCL. So the qurstion looming large is how will the new FireMonkey son-of-VCL measure up? Lars Fosdal has a great blog post showing the difference and thankfully the similarities of the VCL and the new FireMonkey framework, which has is know as FMX.
He sums it up as,
This was just a very shallow outline of some of the differences between VCL and FMX, but it is perhaps enough food for thought to make you realize that you most likely will have to put some effort into moving from VCL to FMX. In some cases, you can get away with minor adjustments, but when it comes to sophisticated GUI – or stuff that is based on Windows functions – you will need to rewrite parts of your code.