Hillbilly,
I asked same question as you in my intended purchase of a JD4710. I'd suggest you do a search here at TBN of old threads on 4 in 1 buckets. There's a ton of information available. To quickly answer, it has marked advantages over the HD bucket. Basically, it acts as a loader, dozer, box scraper, and brush grapple (these are I believe the four functions). You can add a tooth bar as well to give it more aggressive surface digging action. HD bucket is more limited. You won't have your box scraper or grapple functions.
Cons are the up front capital expense. My JD dealer is quoting me, just for the buckets now, $610 for the 73" HD pre-drilled bucket and $1,370 for the 4 in 1 60" bucket with third function hose kit. Still haven't decided myself which one I'll go for ...... but, leaning toward the 4 in 1. Hope this helps.
Regards,
Bob Ancar
Cambridge, NY