Maybe ElkQR is not the most popular site in this niche... but it's effective! It's easy to navigate in the website, and I created my first dynamic QR Code in under 5 minutes (and I take my time discovering all the options...).
I just had a little issue with my custom domain, and the support gave me an answer very quickly. So... it's perfect!
For the future, I hope we can make rounded QR Codes, but for now, ElkQR is a no-brainer: it do what we expect, in a clear and simple interface. Bravo!