Yeah, Transmission is slightly better as it supports protocol encryption. This helps in reducing the chances of being throttled by either local or overseas ISP as well as allowing you to connect to other clients that only allow encrypted connections. Note to private tracker users, some private tracker bans Transmission, so check first.
But it's not easy to use for normal users. Personally, I only run it separately and via the console.
IMO, setting up a http server+ php, for the WebUI, just open up to too many security issues as well as drain resources from an already limited machine.
Use NAS for NAS, other features are only secondary.
BTW: There's no ipfilter or peerguardian ability.