I have the Stihl multi tool, its a great unit and very versatile. Also have an Echo hedge trimmer, I hate it, it is so farkin noisy! It now sits in the shed as a mate who works for AEG has loaned me a 58V Battery Hedge Trimmer, its a little heavy but is an amazing unit. I absolutely love the lack of noise and is easier to throw around than a petrol motor job as there is so little vibration and inner motion from a pumping cylinder motor. He is going to loan me the 18V version soon to compare.
If I was to do again I would still buy the Stihl Kombi, wouldnt be without it and paid for itself on its first outing. But when it comes to the hand helds I would seriously consider the battery operated units. A combination of a pole hedger and a battery hand held is perfect in my opinion.
The thing about hedging is its something you dont do everyday so are able to plan to have the battery charged for the day its required etc.
The other thing about hedging is it always looks soooooo much easier than it actually is. After a half day hedging I am a complete wreck, it is very tough on the body and often a big clean up. One tip on quoting hedging is always ask the customer how much they want trimmed off, are they after trimming.....or renovating? Will it be purely the hedge trimmer, or will the chainsaw/loppers/pruners be coming out too? I also add another 1/3 for cleanup time. And never under $100 an hour.