It depends on what its got. From the looks of it it doesn't have much.
These are nice to have bundled with it because they can be difficult to find, or expensive to purchase as add-ons later on.
Cool stuff to have in a Quadra 630 are (in some order of importance):
1) CommSlot Ethernet Card (that Q630 looks like it may have it, or it could have an internal modem, which is likely Apple's Express Crap).
2) Audio Video Board (looks like it doesn't have it)
3) TV Tuner (looks like it doesn't have it)
Less important, but cool to have too:
4) Quadra 630 MPEG Board
5) DOS Card for Quadra 630
6) Power PC Upgrade Card (not essential, but cool)
If you have 5 and 6 you'll have a computer with THREE Processors, that can run 68K Mac, PPC Mac, and Windows (???).
What's cool about it:
33Mhz Full 040 (if it is a Quadra 630, not an LC/Performa 630)
Supports up to 120GB IDE Hard Drive
Supports up to 68MB RAM (64+4). Some versions have two SIMM slots for 132MB of RAM.
For a quid it looks good, but 9 quid postage? I'd get it if I could PICK IT UP without paying postage.