After receiving an update from this blog mentioning GQueues, I decided to take a look. I ended up reviewing all the instructional videos and playing with the app itself for over an hour. Here is what I posted in their forum afterward:

I ran across GQ tonite, couldn’t resist checking it out. I’m a long
time user of various task managers, since 1998, from stand-alone to
online. I’m currently a power user of Toodledo, which I like a lot.
I think someone did some great work on GQ – the interface is one of
the best I’ve seen, nearly as good as “Things”, which is still the
best I’ve seen. I like all the drag and drop features and how
intuitive it is. And unlimited levels of tasks is great, though,
unfortunately, not useful as implemented.
The reason it’s not very useful is that to create a “Next Actions”
view, it has to be the next 1, 2, or 3 items in each que. This
obviates the usefulness of the multi-level capabilities of GQ (this is
one they’re screaming for on TD, which only has one level of
subtasks). If my que is a major project, then each sub-area is the
highest level in my task list. And my next level down from that might
still be a parent task, not a working task. My “Next Actions” list
will always consist of high level parent tasks, the sub-areas.
Shouldn’t there be a choice for your “Next Actions” smart que that it
be the first (or first 2 or 3) task(s) without a sub-task? That way, I
could have as many levels of parent tasks as I need, but keep my “Next
Actions” list all working level tasks (bottom level, whatever that is
for that set of tasks)?
There are some other fairly obvious features that would be nice, many
of which I saw in these forums. But it seems to me, just based on
watching the tutorials and playing with the software for an hour, that
this would be the big one for me, the one that would keep me from
using GQ because it undermines one of it’s best features, the multi-
levels it can have.
This app sure has a lot of potential though. I’ll check back from time
to time and see how it’s coming along.”

I didn’t mention that the Search capabilities of TD are way beyond what GQ has. Basically, TD is at least one major level of sophistication and features higher than GQ. I’d say GQ would be nearly perfect for my personal life, if I wasn’t already heavily invested in TD. But for someone who doesn’t need something that heavy duty, GQ is a winner.