I use rapeseed oil too. I'm not a big consumer, maybe 10-12 liters since I began a few months ago.
Different pros and cons for me, but my opinion isn't achieved.
One good point, this salad oil is better to breath or to pour on the skin.
It's merely the same price as a discount mineral bar oil, perhaps a little cheaper.
An other one, the filling of the chainsaw is much cleaner, without the long spills of the petroleum oil and much less over fillings.
A very good one, the Stihl's 1/4 turn cap is easy to lock in place.
Considering the gumming...
When I was young, I tried sun flower oil in an electrical chainsaw. Bad idea. It gummed up pretty well, and I had to completely tear down the shaw to clean it.
Now, no problem with the tank, pump and bar / chain. But actually there is some gumming in the hot places : just behind the sprocket, where hot and oily flying wood dust builds up, easy to remove, and around the cylinder's base, compact and hard to remove ( I found that because my 200T has an air leak).
-> Keep an eye on that, because it could prevent part of the engine's cooling. The compressed air can't do nothing, you have to take the engine out of the plastic body and scratch with a screw driver.
For the bar wear, not enough work on it to say something. Even for the chain loosening, it isn't obvious.
What I saw with the 200T, is it stops oiling time to time. The 200T has a poor oiler, not very effective. With this tiny oil, it seems that the oiler can't develop enough pressure to wash out the ships from the exit hole. I don't like to run my chainsaws at hight speed (perhaps the reason-why of the problem), but I have to put it at WOT 1 or 2 seconds when I notice the chain becomes dry: The chain blows out a pack of wood chips, then it works again. I suppose there's an added wear at those moments.
For me, the biggest concern is this oil seems too tiny. Easier to pump, but in the same time it reduces probably the pump efficiency by internal leak (no gasket there). I can't convince my self that it works good with long bars and large woods: some ripping chainsaws have an additional oil tank at the bar tip to give enough oiling in the huge wood, even with tacky mineral oil, so, what with this "hight fluidity" oil ?
I put salad oil too in my ms440 and 066 (50 and 55 cm bars).
But not in the 3120xp, because it doesn't run very often (fear of gumming during long term storage), it has 110 cm bar, it's costly, and ... it isn't mine.