I have been using StarTools for a while and I really like it, and 2 weeks ago I would've been one of those saying "+1 for StarTools", but since starting with PixInsight I couldn't recommend StarTools over PixInsight.
If you're coming from a Photoshop only workflow then you're going to have to learn a new way of doing things in either ST or PI anyway so why not jump straight into PI. Of course PI is a bit more expensive than ST but it's not
that much more expensive and IMO well worth it.
It's hard to explain briefly but the difference in the quality of images I'm getting out of PI after only one week of use really does put all my former efforts using ST+PS to shame.
My advice: get the PI trial, watch Harry's tutorial vids and have a go
