Upload & Sell: Off
In my specific situation, I decided on this lens for some not so uncommon reasons.
1) Canon EOS mount - Olys work well with adapters
2) I have a high resolution full frame DSLR - Canon 5Dmk2
3) Most current lenses are weak in this FL - my Canon 17-40 isn't particularly sharp in the corners on my 5D2
4) Looking for an ultra-wide that was sharp across the full frame (wanted good color, contrast, bokeh)
5) The Nikon 14-24 looks great, but it's too big, has filter issues, expensive / Zeiss 21f2.8 ZE is stellar, but also large, too expensive (for now, but saving for one)
6) The Olympus 21 f3.5 is cheap (recently bought for $300), sharp, very compact & light, good color, solid construction
There are several reasons why the prices are going up for a lot of these older, manual lenses. Mostly because of forums like this one have made demand very high and most importantly, they perform better on the newer, more demanding, high resolution DSLR than many of their modern counterparts for a fraction of the money.