Bit late on the thread here, but I have all three of the following lenses - 135/3.5, 100/2.8, and 85/2, and I like and use them in the opposite order to that...
The 135/3.5 is a perfectly good lens, but it's a length that just doesn't suit my type of photography very often - and like others, I think it's too long to use as a portrait lens.
The 100/2.8 I like and do use a lot, and I'd say it's definitely a much more suitable for portrait work than a 135.
But the gem of the three, for me, is the 85/2. I just love it - its perspective is great, and I love the fast aperture. In fact, it's one of my favourite Zuiko lenses.
But unfortunately, as you've noticed, the order I like them is the same as the order of price - the 85 is by far the most expensive, the 100 is cheaper but can still be pricey, and the 135 is bargain-priced.
Best,
Alan