I can heartily recommend the Shindaiwa, the Speed-Feed head works great and reloading is fast and simple - don't even have to take the string out of the plastic package first. Just look at the trimmer head, line it up so you can see through the holes, poke the string through and run a few arm lengths through. Wind the knob on top and it winds up the string, when it gets close to the head cut it off. Presto - perfectly wound and ready to go, only takes a minute.
I was going to buy a rapid load that uses the pre-cut twizzler pieces, but with all our brickwork in the yard the string gets eaten up fast. Heard about the Shindaiwa and decided to go take a look. Big mistake, came out with a new weedeater :-laf
Definitely the best I have used so far.
I was very tempted to buy another Ryobi 4-stroke as I got extremely good service out of mine. Sadly sometime during the winter water got into my storage shed and I had left the Ryobi on the floor, it was submerged I guess because when I got it out for the 1st spring usage it was rusted to oblivion and the starter rope broke off in my hand :{
The Ryobi will live again though, once I get it running I am going to put the motor on a scooter or bicycle for experimentation

It was a neat little engine, only problem I had with it was the gas lines dissolving (?)