You need to work out what your clients want (a natural golden looking tan, a browner looking tan, a darker tan or the orange fake tan look etc..) then decide what price point you want to be charging those clients so you can rule out the solutions that are out of your price range.
Once you know what your clients want & what price you want to be charging you will have a selection of brands to look at. Make sure to chose a brand that supplies EVERYTHING your range of clients will want, you don't want to be using too many different brands as it just confuses clients.
I chose my solution from a blind trial, I got people to have a free tan and then 2 weeks later return for another tan and fill out questionnaires for the tans. They didn't know what brand tan they were having but I kept a record and then could compare the questionnaire results. I only trialed brands that supplied light tans for my pale clients & myself, right through to darker tans because most of my clients seemed to want natural but brown looking tans with a few clients wanting darker tans. My top 2 solutions were Nouvatan & LA Tan, I cose LA Tan because it was a littlee cheaper and there was nothing else to tip the decision.
I am happy with my choice but have always said if there was a need to change solution then Nouvatan would be the first place I'd go & then look to see if any new brands have appeared (I do always try to keep an eye out and trial any new brands that could possibly provide the same range of solutions I need but with better results or price).
If I lived in a more affluent area I would have been able to look at some of the more expensive brands but I know people wouldn't pay a higher price where I live so I went for lower cost brands and am happy with my decision.
I stock LA FAST, 10%, 12% & Disco (none f the gold range).
For pale people I recommend LA FAST for 3/4 hours or LA 10%.
For pale people wanting more colour I'd say FAST for 5/6 hours or 12%
There are a few clients who love the LA Disco for a really dark tan, they know it won't fade of as well as a lower percent tan would but they love the look and are prepared to deal with the fade off.
I have a few clients who have FAST until they get a natural tan then they swap to the 12% because they love the colour of 12% but find the fade off better with FAST (when they have a natural tan they find the fade off of 12% is fine).