For me personally, the odometer is not an issue is much as I want my speedometer to be accurate. It's annoying that I've got to show one thing to do another.
Its not just yamaha...I had a VTX 1300 and the same thing with it. The speedometer was 5-7 fast on it and by reading their forums it was not uncommon for most of them to be.
On my 06 RSTD, I ordered one today after checking my speed. Using state police issued stalker radar, At 65 mph my speedometer read 70 mph. What I've read it seems complicated to dial it in. The numbers you guys are using, do u just plug those end?
If you decide to buy one...will you post some pics to see how it looks. I've been kicking the idea around especially if it doesn't require any modifications to the bike.