I use a cheap, but good Echo. I bought an after-market head that usually holds plastic "blades" and I replaced the blades by pinning in the same length in chainsaw chain links (without the cutter and drag, JUST the chain lengths themselves.)
I then grind-sharpen the very tip of the end of the chain length so that it "cuts" instead of 'Whacks",,,, It lasts for years and there isn't a weed made that can hold up to its force. BTW, wear BOOTS while operating it. It ain't no toy,,,,
