yeh ive used it lots, with some time saving ups and amazing errors on the lows.
You can have them in part and assemblies and it can be used to save lots of time when making different versions of your assembly. But if your not to good with it, it can make all your models fall apart with not much help finding whats causing it.
Its really gets good when you use design tables to drive your models, drawings and assemblies, which is an excel spreadsheet that drives solidworks in many areas (including colours and such).
Great bit of kit, but when it goes bad your looking at all of your work looking like a mess.
Not being funny but if you say your good at solidworks you should be using configs already to save time. But give it a go in a few simple parts and assemblies and you will pick it up.
You can have the same dimensions controlling a sketch that is different in each config or maybe a plate one with holes and one without. In assemblies you can supress mates and parts giving your say a house with the windows open and one with them closed without deleting the 'windows' or mates, just suppressing the closed mates and adding new open mates and so on.
Good luck.
