I really hate BancNet's BIR eFPS interface. It has got to be one of the lamest implementation of BIR's electronic filing and payment system. The brain dead system becomes evident from the time you enroll. The fields cannot be filled-up by typing, but by copying-and-pasting. That is the weirdest thing ever and took me quite a long time to figure out.
Once you get past the enrollment stage, using it every time also makes you feel like you are back in the mid-90's. The user interface, with those large frames, is reminiscent of the early years of the World Wide Web. It is just so plain ugly. If there is a reverse Web Awards (ie. the ugliest of the web), they have got to be nominated.
Oh, and it only works with Microsoft IE? Duh! What kind of website nowadays still requires only IE?
I've been using BDO Corporate Internet Banking's eFPS for a long time. While the user interface is also another blast-in-the-past, the flow is not as bad as BancNet's. I think BPI Expresslink's eFPS interface is the cleanest and simplest.