some of this is personal to my riding style but is hopefully going to give you some insight.
Had alpinestars back in 2003, bought them cheap in Italy when on a ski ing holiday. Very comfy, good support for your feet but the uppers are soft. I tend to rub the inside of my boots on the frame, I wore through the alpinestars in a month !
Forma / gaerne as others have said not a lot of support, had both. Forma where at least comfortable, I found the gaernes very uncomfortable as they took the skin off my ankle first time out so went on ebay.
I currently have sidi, very comfy, soles are very good and provide good support, ankle support not as good, I have twisted an ankle in them.
Rainers which are imported by Birketts are probably the best vfm boot I have had in recent years and i'll be going back to them next. Rainers are not that trendy but they do the job, they are padded internally and last a year of major trials including the SSDT etc. I stopped using them when I got given a new set of Gaernes as part of a deal on a sherco, I have been round the houses since but really, despite spending more, I haven't found anything that suits me better.