hello,
I'm at the opposite end, doing only 95% construction with a occasional pruning/mulch/edging job here and there.
I think the key is to become good at what you do first, then move on. What I mean is, if you do maintenance only, then stick to that until the day comes that you say, "this is too easy", or til you have a good system/good employees that can run the maintenance while you begin to concentrate on other aspects of the business.
construction work does require a completely diff't set up. It also requires a lot of time to do well. You will find that hours upon hours of time our spent on estimates, plans, locating plants, scheduling supplies, mobilizing equip. etc, etc. If you don't have your act together in your maintenance division, then the time you spend doing constuction will start to affect the operation of your mowing crews.
My opinion is that the real money is in construction, so thats why I stick to it. Not to say that there isn't money in maintenance, as there surely is, but the big money jobs for me come from construction. What is made in a week mowing can often be made in 2 days doing a install.
The main thing is to stick with what you like. If maintenance is your thing, then don't think you have to move into construction because there's bigger $. If thats the philosophy you are using to make the switch, then why not become a stock broker instead, as construction work can be just as different of a business from maintenance as the stock market is.
On the other hand, you already have the trucks, a majority of the equipment, and some of the basic know-hows to do construction, so it is somewhat of a logical transition.
steveair