Well, it's going to be completely different software. UB is outdated and older than my gran. Check out the infamous bleh (with an a) and that's what the new software is. It's more versatile and mods can be added (like thank-you buttons, groups, personal pages, announcements which can appear in every forum and so on) and in-line formatting.
It's basically better in every way possible.
I've spent about 3 years as a mod/admin for vb boards and they're extremely powerful.
what's wrong with this bb other than it's old? is it too slow to run on the host or something? too bad if this board loses the "show all" feature, I hate to click hundred of pages to read a thread...