I've handled them both the 327 and the telescoping Stihls, and had a HT75 breifly. I bought an echo ppt-280 last year. You should be able to order one online through HD, but I'd always recommend your local dealer.
Just my thoughts. I'd recommend you start out with a set of Jameson or Marvin fiberglass poles. Your stihl dealer should be able or order a set. Stihl re brands Marvin poles as PP900 or something like that. I truly get way more out of my fiberglass poles than my ppt-280. I also climb, so that is also an option to remove large branches.
As far as comparing the stihl and husky options. The 131 has the torque to rest the bar and the chain on a branch and start cutting from idle. My ppt-280 and mostly likely the 25cc husky will need some chain speed before cutting, meaning you'll need to hold it able the branch prior to cutting. This will wear your upper body. With the glass pole, hoist it up, rest it on the branch, a few pulls and gravity does most of the work.
The HT75 I had wil have a simillar design if not the the same drive tube and shaft as the HT131. It is 1" od and flexes quite a bit a full extension. It is also known to bend beyond repair and need replacement.
The husky tube is aluminun and of larger diameter than the stihl. It is stepped down in diameter to accept the cutting attachment. I see the husky tube is being slightly stiffer.
The Echo tube is WAY bigger than the stihl and much more robust, and also heavier. You can add an addtional 3ft if your like too with the echo. The engine is OK at 1.2hp, not like the 1.4 or 1.9 of the stihls so don't expect power, but rather more durability in the drive tube section.
Just my thoughts..
You can always grab a KM set up as well and add the extensions.
Airframefixer
