All interesting and valid opinions but I have a slightly different take on this.
You will notice that I didn't suggest the OP buy a '58, I suggested he audition it. I don't feel I (or anyone else) am qualified to make a definitive recommendation until we've heard it and (this is the important bit) the OP has a chance to hear/feel how the mic reacts to their voice.
All the mics on my list are ones I use regularly. The band I regularly do live sound for all started off with '58s, now, on my recommendation they are on a mix of Audix, Sennheiser and EV. Depping guests get the chance to use their own but if it's bobbins they will be told. I wouldn't lose any friends over it but they generally take the advice well.
As a singer I've used a variety of stage mics. My favourite for years (always welcomed by old school FOH guys) was a Beyer Soundstar II which I found made me sing better. It wasn't a "detail" or "air" thing or just being able to hear myself over the din, it just reacted in a way that encouraged me to experiment and stretch myself. It died when some crazy dancers got tangled in the mic lead and whipped it across the room where it disintegrated under 100 stamping feet.
Nowadays I have my choice of the above, and others, including Beyers and EV. I find they make me sing differently. The OM-7 is a good mic to turn up loud and sing gently into, as is the e935. This is not something normally associated with the OM-7. I didn't like the kms105 because, although it sounded silky and beautifully detailed (and retailed) it didn't give me any particular "angle" to work with, it was soul-less. The woman who came after me whose mic it was made it sound sublime.
If you have the right voice the '58 makes you sing from either your throat or your resonant chest cavities. If you choose the former you will have a permanent sore throat, if the latter you can sing forever without strain and fill the room with strong and melodic, if not very detailed, richness. It's a bit lo-res, but so am I.