Finally Linode moved to hourly billing, following DigitalOcean's model (hourly billing by default, capped at the monthly price). I don't see Linode moving more into DO's territory: Linode's cheapest instance costs four times more than DO's, but it is also more powerful and only comparable to a similarly priced instance on DO.
Since I switched from Linode to DO, I missed the advanced console and admin tools provided by the former, not to mention the 8 virtual cores (not guaranteed, but available most of the time when I was using it); switching back is now a concrete possibility, the absence of hourly billing was the real show-stopper for me.
Introducing hourly billing. Now you can enjoy Linode services billed in hour increments, add services to your account without needing to pre-pay, and be invoiced at the end of each month only for the hours you used.