Vintage lenses: which is the best ?

I'm going to buy some lenses for my E-PL1.

I found some lenses and I would like to buy one of them.

Which is the best amone the ones below:

1) SOLIGOR 75-260

2) PORST 75-260

3) HOYA 75-260

4) HELIOS 75-150

I would use them most for portraits (and I need a nice bokeh, if possible) and sometimes to take photos about architecture or nature quite far from me

I would like to buy Helios but I didn't know they produced a zoom focal leght. I knew they produced only fixed focal lenght, just like i could see in Wikipedia (http://en.wikipedia.org/wiki/Helios_%28lens_brand%29)

What would you suggest me?