So cloudflare goes down or effected by any reason, all website that use cloudflare is going to be effected. This means you are hostage to a centralized service. I don't know how long the site was down but imagine how powerful cloudflare is becoming by collecting all data from their clients.
The forum itself is a centralized service and has a centralized server being hosted somewhere.
In terms of reliability, cloud flare is a net benefit, as it has the ability to stop/mitigate ~all DDOS attacks and is generally reliable.
There are factors unrelated to reliably, such as privacy and the potential for CF to execute a mitm attack that are a negative to using cf