Depends what level you're playing at, how good your serve is, and how well your start matches.
Sub 4.5/5.0 (depending on how strong your serve is) probably isn't going to make much of a difference. But 4.5+ (and if your serve is a weapon) it allows you to take the initiative to your opponent. I'd say its psychological more than anything else. Have you not played matches where you begin serving like a bat out of hell and noticed the look on your opponent face - how am I going to beat this guy? But then again, it doesn't bother some opponents.
Above that level, I suspect any advantage is negligible because everyone should be able to serve well at that level unless you end up with some sort of crazy Isner / Mahut type match where Isner had the slight advantage in having the safety net of being lose an extra point over Mahut.
Tennis is very obsessive about switching sides, serves, ad court, deuce court, and adding the rules about winning by two. So if you get beat, accept it. Don't say that you had no chance because you lost the spin.
Last year in sectionals we won the toss and defferred. The other team chose to recieve and we chose to serve with the sun in our eyes.
As soon as they realized they would also have to serve into the sun on their first service game they wanted to change their choice. When we would not let them change they got upset and a real contentious match ensued.
I would love to say that outmaneuvering them on the toss made a difference but we lost a very close match .... with the official watching lines because we neded someone to watch them closely.