im 100 per cent TRAD and can do virtually any windows including above connys.im v.good with all sizes of extension poles and swivel squeegys,ladders etc.been at it 15 yrs. 
and im doing well but want to try WFP,im keeping an open mind.ive picked up some work lately of a few WFPolers.mainly cos of water all over the place,spotting,etc and they prefer me with ladders or TRAD pole and dry windows ;Dbut i can imagine cleaner frames and extras being easier and faster to clean?im sure if i had WFP i would pick up more work and fit more in on big houses and leaded/georgian anyway and keep my compact work{2 wks in every month}TRAD?any thoughts?be honest 
Once you get used to it, you will earn more money with WFP. The turnover will be higher (or do the same work in less time). The outgoings will be higher too. However, the gap between turnover and outgoings is much bigger than it used to be.
It's all very well customers saying they prefer you on ladders. Maybe ask them again when they are about to scrape you up off their patio?
I haven't lost any work on quality issues for ages - until today. I was thinking of cancelling anyway because she is extremely fussy and used to complain even when I cleaned for her the trad way. It seems odd that she has tolerated WFP for over 3 years without a murmur and suddenly she wants her mother's (trad) W/C to do them. The daft bit is that he probably won't be able to get to them all because that conservatory is BIIIIIIIIIIIIG.
I know what you mean about the swivloc applicators and squeegees. I used them a lot when working trad. It amazes me that most trad W/Cs don't invest in such basic tools - especially the so called zero degree squeegee. In fact, I started using the swivel applicator as standard because I found it saved on wrist ache if the applicator did the swivelling rather than my wrist.
The truth is that I earn more, with the right investment am able to do jobs that I couldn't do at one time, and there is less chance of W/Cing putting me in my box. Although I have lost an occasional job because a customer would rather someone risk their neck, the work I've gained is far, far greater.
I won't say that WFP is a magic wand but on most jobs, most of the time, it's as good as trad - if the operator uses it correctly. Sometimes, it doesn't work so well. I had a job recently where there was dark coated glass in a reception area. I ended up needing to finish the outside trad because it just wasn't taking to WFP. Presumably some chemical in the coating was reacting with the pure water.