We use dep, and have been pretty happy with it so far.
It takes care of everything that we need as far as locking down dependencies, and some say the workflow is pretty similar to python’s requirements.txt
This short essay has been long overdue, but I’m writing it in order to have a short post I can link to whenever people do a pull request for a Gemfile – which leads to a rabbit-hole-esque discussion about why we don’t like bundler.
If your answer is for listing dependencies, making sure you lock down versions of gems, then our answer is pretty much the same – and we probably fall into 99% of all the other people needing bundler.
The short answer is convenience. But really, there has been a huge backlash about this, and most advanced users prefer explicitly requiring over having bundler do it’s “magic”.
Not to mention, when you add bundler to your runtime, you pretty much add 10-15MB into your app’s runtime, which is memory best used for other more important stuff.
In some cases, you absolutely need a Gemfile (and a Gemfile.lock).
Heroku is probably the most glaring example of this, since they’ve deprecated the .gems file format starting with the Cedar stack.
For that case, I have a gemfile gem in order to generate a Gemfile from the listed gems.