i Have the kombi blower and i upgraded to the stihl br600. it is a huge difference. i even have the km130, which is stronger then your 90. i also have a walk behind blower 13hp (390cc honda engine). the stihl back pack blower br600 works alot better for getting the leaves of out ivy, but if its a ton of sq ft of ivy i might use the walk behind blower.
the back pack blower is a huge different from the kombi blower. it youre going to be doing fall clean ups, it will help out alot.