they all have there good and bad points.
looks is personal opinion, the ssqv looks one of the neatest though.
sound is personal prefference too. my favourite is the GReddy type s
fitment. if you still have the efi pipe then the bet by far is the arc, as easy to fit as the stock bov. all the others are pretty much the same thing, adapter pipe and some jubilee clips and cable ties.
lifespan. anything with a piston should last longer than any of the diaphragm types. if you buy second had give it a good clean up and grease and it should last a good while before causing any problems.