I am in the market for one of the combo tools. Uses will be string trimmer and blade edger most often. Less frequently will be using the cultivator and pole saw.

Anyone have any advice or insight on these systems?

You need to try handling them at the dealer with the engine and tool head you are looking at. I have the kombi system with the most powerful engine. Depending on the tool head, it can be pretty heavy. Of course, I’m 71 and someone younger may not have any issues. I have the cultivator, bed edger, sweeper, and trimmer ( thrown in for free).

I have the Kombi. only issue I had was with the carb after not running it for a while, cheaper to replace than rebuild. I have a number of attachments the pole saw can be a bit heavy after a while, but that's just the nature of it

I have PAS for this and have been very happy. That assumes you can live within the power limits of the product, I have dedicated stuff when that's not realistic like pole trimmers. I have just about all the options. THE big issue to me is that if you get Stihl their distribution system limits you to the local dealer. If you get PAS and need a new powerhead its just an amazon order away.

I have the largest Kombi w pole saw, hedge trimmer, blower, and string trimmer head.
It’s heavy but 7 years old w no issues whatsoever.
It’s a do over if I ever needed another one.

I have a second hand Stihl FS85 that is probably 15 years old. It isn't a split boom, but I can use the attachments on it. I have a saw blade, string trimmer, pole saw, and scythe for it. I use the scythe as a hedge trimmer as well. It does get heavy while using the attachments in the air. However, they all work great. If anything should happen to this trimmer, I will replace it with another Stihl.

There is literally no relation to a pre emissions unit to what you get now.

I’ve got to the Sthil K55 combo. String trimmer and fixed blade edger. Thirteen years old, replaced the carb one with some cheap aftermarket from eBay for $13. Sthil was asking $85.

Pretty happy with it. All pieces were $300