I agree about the 448/485 hoe - it's a good match IMHO for my 3320. The mount/dismount is a bit of pain, the rock shaft arms don't lift the hoe onto the pins like their supposed so you end up having to fiddle with the stabilizers and the dipper to position the BH on the tractor frame. It's not a big deal once you get the hang of it.
You will need to remove all the 3 PH stuff. The BH is frame mounted and does not run off the PTO - you need a rear hydraulics kit. I use the BH more then I thought I would and I generally mount it in the spring and it stays on-board until late fall when I set up for plowing and don't do any digging for a few months. If I switch implements a lot and needed light duty digging capacity I'd probably be a little more irritated about the mounting thing. But even if it quickly lifted the BH into position, I'd still need to remove and re-install 3 PH parts if I was changing up implements - it's not as easy as dropping one and picking up another.
But overall, the capacity upgrade is worth it depending on what you're doing. I've beat the crap out of mine ditching and pulling stumps and the only problem's been a hydraulic fitting on the upper arm that failed somehow. It was a cheap and easy fix. A friend of mine was ditching with a 3320 and the smaller BH and bent his stabilizer arms, which are constructed entirely differently then mine.
I don't know if the thumb option was an option for the 448; had I known about that I would likely have gotten it. I have a grapple bucket and can live without a thumb on the BH, but it would be handy for tree and stump removal just the same.
I often wish for more buckets - I have the standard 12" with teeth and I'd almost rather have a 6" with teeth and a 24" for grading.