I had mine done about 20 years back!
It was Colour me Beautiful.
I was disappointed as she said i was on the cusp of 2 types!
anywa, one thing it did do was sterr me away from black and navy and give me confidence to try neutrals and ecru shades, as well as other colours.
I bought the book Colour me Confident a while back and it's good.
I think the problem with DIY is that you are not always the best judge of what really suits you. eg I used to LOVE peachy shades but realise that although I like them, they don't like me and make me look washed out.
The bottom line seems to be - are you a warm person who suits golds, browns, etc or a cool person who suits cooler shades.
I look drab in khaki and moss green,(warm) but suit blue-greens.
It's worth having done, IMO and there is also House of Colour, not just CMB.