I might not have been clear-- I didn't buy the Kombi setup because it seemed like it didn't save money.
I have an FS90 or FS91 straight shaft IIRC, I'd have to confirm.
I also have an edger but don't remember the model.
Fs91R is $360 + FC91 is $400 = $760
KM91r is $360 + trimmer attachment $105 + Edger $200 = $665
So there is some savings. But if you bought a lower line edger as most people that are not lawn pros, then yea they would be somewhat comparable in price but it’s not an apples to apples comparison
When I was mowing lawns on the side 10 years ago I had a FS90r. I used an edgit rotary guard on it which allowed easy maintenance edging.
https://edgit.com/products/edgit-pro
It is the berries for trimming fence post, chain link fences and foundations, much faster, easier and less frustrating than a standard back guard.
I would swap out the speed feed trimmer head for the tri brush blade when knocking back brambles, multiflora rose bush, and young russian olives sprouts but you had to remove the edgit as well. With the kombi I just swap heads.
I do really miss the flippy gas cap on the FS90r
The blackberry canes are pretty tough. You can gnaw through them- slowly- one at a time. The Echo PAS looks pretty good, although it adds up by the time you buy attachments. I guess I could buy the head and the brush cutter, then start saving up for the string trimmer for when my old Husky finally croaks.
If you are only going to swap between trimmer heads and a brush blade for brambles it’s pretty quick to swap on a standard trimmer with a solid shaft. You just insert a rod into the head and turn off the trimmer head. Install the blade with a blade rider and nut and tighten with the scrench and remove the rod. Take 2 mins.
Echo x series trimmers can be bought with a solid shaft such as the SRM-2620. Be aware they sell the same machine with a flexible shaft, the will have a T at the end such as the SRM-2620T. You can not use the T models with brush blades.