Bang for your buck is relative. Technically, you get more stuff for less money with Digi, because you do not have to buy the separate audio app. Then, later, if you want to use Cubase or something, you can do that too (they have ASIO drivers). So I would say that other systems where you have to buy the app separately from the hardware are actually "less" bang for your buck.
HOWEVER--
All version of Pro Tools LE (no matter what hardware you buy) are limited to 32 tracks of audio. So if you absolutely need more than 32 tracks, it's not the way to go.
HOWEVER #2--
The MOTU boxes DO include an app, AudioDesk. It's just not their best app (Digital Performer). And again, both apps are Mac only, they do not include PC software, apart from the drivers.
FINALLY--
From what I have seen of the Digi002, it is the one I would get if I had it to do all over again. It has better converters, 4 mic pres, is 96k capable (something I really don't care about, except that it makes the converters better on the bit rates I use), and that control surface is killer.
For most people, the differences between the apps and their functionality will be trivial. There are definitely people who would be hampered by Pro Tools' MIDI implementation, which definitely does not kick ass. There are definitely people who would rely on the VST instrument support of Cubase for their sound creation process. There are also people who would find Pro Tools to be an easier editing environment, or vice versa. The bottom line is, for most people using it as an audio recording, editing, and mixing environment, anything you use and learn is going to be what you like.
Also, you should know that it is quite fashionable to hate Digidesign and Digidesign products, so if you buy Digidesign, you are instantly going to be marked, and criticized by some... If you decide to go Digi, learn to use the DUC (Digi User Conference)... it's very useful.
http://duc.digidesign.com