Hi Sean and welcome to Cleanitup!
If you haven't already done so, read over the Welcome Message post on both of the window cleaning boards, and remember to fill in a bit more of your profile, (see the top bar for that) your signature, and personal text, so we get to know a bit more about you.
If you'd like to use the search button, on the same bar, to look for posts by Justin R who has started out quite recently in window cleaning - solely with wfp. And also for posts by Philip Hanson who has now gone completely wfp from ladders. Or even just a search on wfp!
Exclusively residential? I couldn't use wfp exclusively on most of my residential jobs, but you'll know what'll work for you. The commercial jobs I use it for still have to get the insides done by "hand".
Worth it? Well there's the initial expense - but that's tempered by the increase in speed with which you'll get through your work.
I'm sure others here will add their comments, but are you able to contact any wfp users close to you for some practical tips and hints?
All the best for whatever you decide.