CAE, first of all, what year is your B7100, ie, does it have a belly PTO? That will make a big difference on the availability of a front snow blower. In answer to your first question, I like (and have) a front snow blower, so that is the one I can speak about. I can't turn and watch a rear implement as easy as I used to. In answer to your second question, it depends on whether you have the mid pto. If you do, new ones are available and priced accordingly. I don't have any experience with them, but I am sure others can chime in. If you don't have the mid pto, then you are looking for a used B748 like this one that I restored:
https://picasaweb.google.com/110263893958737890068/KubotaB748bSnowCaster
It uses a front pto that drives off of the front of the crank shaft. They are hard to find, especially good pto's, but are around at $600 to $1200 if you watch ebay, craigslist, etc.
Good luck,
John