Okay, well it seems that the logical way to approach this is to analyse the two things. I never used DDI much, but I vaguely recall that it was an online-only character builder and monster database, and that it cost about £4 a month per person. Is this correct? The two things worth comparing here are:
1) Price, probably done per person and per group over the course of a month and a year.
2) Content, including suitability for use at the table and for game preparation.
On point one, I can't run the numbers since I don't really know how much DDI cost. On point two, we'd certainly need to discuss the problematic delivery of the content for DDI (i.e. the online-only website thing), but give it props for being a subscription that let you avoid buying books. (Since I think that the ground around the idea that this feature turned out to be bad for the company's ability to make profits is well trodden, we can probably pass over that as irrelevant and likely to start arguments rather than helpfully advance the conversation.)
It was $70/year - not going to check the conversion rates.

Sharing for a group was the norm, not the exception.
The earlier builders were thick clients which ran on PCs. (These still run today, btw, and have been updated by fans; my table still uses them.) These received, AFAIR, universally positive reviews.
The later ones were web-based, using (ugh) Silverlight because WotC is phyiscally near Microsoft, and there were a lot of Silverlight developers looking for work after MS started to drop support for the platform. (Yes, this is was
bad idea, but I suppose when you're looking for developers on the cheap...) They are nevertheless very functional and contain all the content - and they are still available, today.
There was no app support at the time, but it was also a different marketplace from today - smartphones and tablets weren't as ubiquitous in 2008-2009, after all, and those that existed were a lot less powerful. Mobile support, OTOH, is essential for a new product offering, today. So any comparison of platform is going to be shaky; PC (and later PC/Mac browser) was sufficient at the time of its release, just as a cross-platform app is sufficient today.