I used House of Colour and found it fantastic.
The person had lots of different coloured scarves and first of all worked out what season I was i.e. spring/summer/autumn /winter.
They then went through every colour scarf within the season- holding a scarf beneath your face to see how your face looked with the colours. They also explained what they were looking for and I could absolutely see which ones looked better and which ones didn't. The colours were also rated as being the best colours for me or ones only to wear a bit of or avoid. Then finally I was given a booklet with colour samples to use when shopping and a booklet with more information.
I have found it very useful and it is one tool in working out whether something will look good. It makes shopping faster as well but I am not a slave to the colors.
I was fairly straightforward to categorise I think, however my husband wasn't straightforward at all (he saw it being done - laughed about it - then got interested and then wanted his colours 'done'). I think that it needed someone who knew what they were doing to work it out - he seems to sit between/across seasons. There were several of us there and we could see what the consultant meant when using the different colours.
I think that many people work out naturally themselves but for me it gave me confidence and an understanding of why something hadn't looked right in the past even though it was an autumn color. I am not sure how you get the full detail in an online consultation.