Resque vs Sidekiq?

From the question:

In particular I would like to know is there a way to monitor programmatically whether a job is completed in sidekiq

Here's a solution for that:

1. Sidekiq::Status gem
2. Batch API (Sidekiq Pro) - usage

Resque:

Pros:

• does not require thread safety (works with pretty much any gem out there);
• has no interpreter preference (you can use any ruby);
  Resque currently supports MRI 2.3.0 or later
• loads of plugins.

Cons

• runs a process per worker (uses more memory);
• does not retry jobs (out of the box, anyway).

Sidekiq:

Pros

• runs thread per worker (uses much less memory);
• less forking (works faster);
• more options out of the box.

Cons

• [huge] requires thread-safety of your code and all dependencies. If you run thread-unsafe code with threads, you're asking for trouble;
• works on some rubies better than others (jruby is recommended, efficiency on MRI is decreased due to GVL (global VM lock)).