Personaly, the whole flash van, uniform, hot water system, letter full of over-complicated dribble thing is a big put off for most domestic customers.
You give them your price, they look at what you've got & think, sod that, i'm not paying for his new van, flashy equipment etc! They certainley don't want you to be earning as much as them.
All they want is clean windows, you to be reliable, respectable, polite etc. none of which requires vew vans, hot wfp's etc.(or wfp at all )
On larger commercial jobs it's probably an advantage & on some (cream of the crop) domestic but in (real world) general domestic terms i'd say it's a disadvantage, it's all got to be payed for.
I know the kind of posts you're reffering to dave, sometimes i wonder who they are trying to convince, themselves maybe?
Common sense & a bit of drive is what counts more IMO. We are window cleaners at the end of the day, we've not done years at college studying our craft, it's not what most people consider a skilled job. If you turned up at my house with 20k worth of van & equipment to clean my windows & gave me a quote which reflected this, i, personaly would laugh & tell you where to go. You can drive your business forward & reap the rewards without such expense but you can't run before you can walk either.

Just my 2 pennys worth as per.
Tony