I used the same 7 yr vinyl on my boat as I use on my company trucks, no issues with either. Boat has been on for 3 yrs, trucks upwards of 18, on the 18 yr old one, the last 2-3 have really started to have issues. The boat, I will assume due to the salt water, is fading a bit more in the same time frame vs the trucks. BUT, still overall, doing fine.
As mentioned, do NOT skimp on the vinyl quality, that part of the whole equation of things is cheap! Labor is the same no matter which way you go. In y case, about 300 for the lettering on my boat, to save $20 and have to spend an additional 300 the following yr........not much of a savings thank you very much!
Like all things great and small, for those thinking $300 is high, it all depends upon the lettering you get, time involved etc. I have a two tone lettering, sides, and transom along with the st and city. For what I got, I thought pretty reasonable from my sign guy!
Marty