Every day I post an #TTRPG thought of the day on Twitter. I recently did a month long analysis of con sign up systems. My summary was:
There are three main types of sign up systems:
Micromanagement, Prebooking, Sign up on the day.
There are some combo systems - the prime example being the Garrison cons which use a bit of micromanagement backed up with sign up on the day.
None are perfect. All are gameable by unscrupulous people determined to get the game they want.
I concluded that the best one was micromanagement. Typified by the many pop-up cons being organised through Twitter these days, everyone sends their requests in to the convention organisers (via Twitter) and they personally allocate everyone to the games. Personal ,friendly, labour intensive and gets more untenable as a convention grows or lengthens.
Second best was prebooking. Allows Referees and players to know what's going on before the event so they can plan. Putting aside UKGE's bespoke system, the best of these I'm aware of is WarHorn. If you're planning a convention you need to have a good reason NOT to use WarHorn. However, you need to use it and not let it use you. Its use needs to be well managed and monitored by the convention organisers. Possibly lacks flexibility over a longer event.
Coming in last, but still popular amongst some old guard is sign-up sheets. Easy to use, social, spontaneous and the only system which can be physically dangerous to use. Additional systems required to make it functional, fair and safe - especially at larger events.
A bit late to the party, but here goes:
I've only used Warhorn for offering games at ConTingency, never as a player, so I can't comment on those aspects.
The most I can say about Warhorn is that it works, and has thus far failed to annoy me. Given my near constant state of irritation at almost every aspect of technological 'progress', that's no small thing (why yes, I am a software developer, does it show?)
I find the daily schedule to be a little hard to scroll through when there are a lot of games, it would be nicer if it split them by slot. I like the personal con schedule it gives you, that's handy.