Not sure which model, but I have a stihl ergo-start, that's fantastic. It's easy enough for me to start, and it has a shoulder strap (not as useful as a harness), but as long as you don't have a dodgy back or shoulders is great, the strap is easily adjustable (it's like the shortener on handbags), so you can use it no matter how tall or short you are. The model I have has an optional brushcutter you can use, I've never bothered to buy it as the stuff I tend to use it on is this year's growth. You will definitely need eye and ear protection, and I'd strongly recommend using wellies or stout shoes and gaiters as some of the chopped-up bits get thrown out at a rate of knotts. Try not to pull out to much strimming line, I had a small bruise on my knee for ages after!
Get some decent gloves, too, with a bit of padding, they will protect you from any vibrations or knocks if you accidentally hit something with a strong stem.
Not cheap, but I bought a cheap one before the stihl, and it didn't last very long - only just until it was out of guarantee.