I fly an avid flyer with a heavy hauler wing so my mileage may vary. I bought my VGs from land shorter.com due to price more than anything. I placed them 10% back from the leading edge and spaced roughly 2" I believe. Not saying it is a miracle but I am definitely a believer. I will state my performance changes and let you judge whether it is worth it to you. For me it was. My stall went from 40ish to 37ish no noted change in top end. prior to VGs my landings when approaching the flair my wings would rock back and forth as they were losing lift ( at least that is what they felt like) Now the wings are rock steady all the way to the ground and it has given me much more confidence in slipping over the power lines to land on my 1000' grass runway. That in and of itself is why I am so in favor of them for no other reason. To me the stall difference is not a big enough change to worry about but it did change. I also put VG on the underside of my horizontal stab approx 1" apart not sure I really noticed much more pitch authority but I do get a warm and fuzzy feeling and would probably do that again anyway. As far as cleaning the wing to me just wipe front to back with a wet rag and I don't have problems cleaning. Hope this helps a bit
Mark