I also had a great experience with HA Proxy open source support. We had some sort of config problem when we enabled H2 (IIRC, maybe it was going to 1.8 from 1.7). I did a bunch of testing of it, documented what I found and where I found it acting funny, and posted to the haproxy mailing list. A dev replied with something like "Sounds like you have this config option set wrong". Problem solved!

We had bought a ton of Fortinet gear to firewall+load balance for us, but in the end could never quite get it deployed. I got the haproxy set up instead and it's been amazing!