Well I play in Open and solo depending on situation and whether I want possibility of somebody messing with my plans. Best of both worlds I say. Need to visit somewhere like Deciat. Solo mode on. Do some serious mining, solo mode on. Flying routine flight and not doing anything particularly important, Open is good choice. Wanting to see sometimes silly action, Shinrarta Dhezra in open....especially as if you fly some mean looking ship you can stay as spectator most timesAt the risk of sounding argumentative (which i am i admit).
I hate PVP, i am absolutely crap at it, in this game and every other game i have played it in. I love open for the fun interactions with other players, that is why i play in Open and i encourage people to give it a try and not be turned off by the forums overwhelming suggestion that you will ganked the second you poke your head in. Open has more to offer than just PVP.