I have used 1,2&3 in the past. My preference is for the 2's as i felt the toe area on the 3's was a little tight and the mesh was quite light resulting in my big toes bursting out after only about 200 miles. so my perfectly good lunarglide 3's are now just used for trails etc (i dont do much trail running so these will do for now).
I got a good deal on a pair of 4's (£66 sports direct) and at the minute i think they are the best yet, snug comfortable fit, really springy ride (as with all the previous ones), roomy in the toe area and better looking than the others, so I would really recommend them. Of course i may update this post if my toes end up bursting out in a few hundred miles!