HDD Utility Disc 1.10 only allows you to boot installed programs from the HDD (if they are allowed to boot from the HDD) and to store saves from Memory Cards on the HDD. It makes the HDD appear in the Browser, adds a Move option when dealing with save files, and adds Mouse and Keyboard option to the System Configuration menu.
As for successful PSBBN installs on a non-Japanese system, I've heard of a few, if you loosely define success. They require a modchip and/or Linux and a patched PSBBN 0.30 disc. Sound is disabled when the program boots, and all features result in errors except for Memory Card backup. A lot of the program is online, so DNAS locks those areas out, and the rest just won't work with the patched version.
Therefore, HDD Utility Disc offers better features for the disc space used if you don't have a Japanese system, as it's a lot of trouble to get PSBBN to run at all on a non-Japanese system, and you have access to the same set of features on a non-Japanese system.
My PlayStation2 HDD guide.
NTSC J SCPH 30000 with HDD and PSBBN 0.32
NTSC U/C SCPH 30001R Astral Blue LE PS2
Final Fantasy XI status:
Server - Ragnarok, Race - Mithra, Jobs - BLM 72 WHM 51 SCH 39 SMN 25, Nationality - Windurst, Name - Bungiefan