Dungeon Delves - the perfect format?

One of the problems often mentioned with RPG's in general is the time investment. First you have to spend one or several (often the latter) evenings, and on top of that, the GM have to prepare the adventures, something that shouldn't be taken for granted.

Dear Wizards have tried to solve that with what they call the Dungeon Delves. They are short adventures for DnD 4th of three encounters each, and each encounter is designed to take about an hour. There's also a book with a collection of Delves, meant to take you from lvl1 to lvl 30.

That means that if you have an hour to spare, you can play a short session. We are a couple of gamers that is trying this out on the lunch hour of the university we are all attending.

The impression so far is that it works. The modules are nice enough, and so far the encounters do stay within the time slot. So, what are our impressions so far?

• As said, the timing works quite nice. The GM has to setup the place a couple of minutes before, but other than that one encounter is roughly one hour (and sometimes less)
• The delves are VERY combat oriented. If you prefer other types of roleplaying, they may not be for you.
• The encounters are nicely balanced so that they provide a challenge, without being to lethal. You have to be careful with your resources (like Daily Powers) so that you have some oomph left for the final encounter. There are also guidelines for how to balance the encounters if you have to many or to few characters.
• The encounters use the environment quite nicely. For instance, in one of the encounters, some kobolds pushed over a large statue on one of the characters (who got stuck under it for 3 or 4 rounds).
  

Of course, while playing through the encounters, I've been toying with the idea of spreading the idea to other games and settings. Even to other types of encounters within DnD 4th, like an interesting skill challenge.

I think that "bite-sized" roleplaying has a place and is possible. Maybe we just have to think a little different and modulize our adventures a little more.