Is there an alternative to rEFIt as a bootloader where you can choose between OS X and Ubuntu? I already installed Ubuntu on my Mac with rEFIt, so if there's a better option, I can remove it now.
I'm exploring, mainly because I want one with a more appealing UI. Other improvements are still very much welcome, though.
It's been over two years since rEFIt has been updated, which is why I forked the rEFInd project from rEFIt. rEFInd includes a number of improvements, many of them related to directly booting Linux kernels with EFI stub loader support.
There's elilo
elilo (the efi linux loader), is the EFI equivalent of LILO, a linux boot-loader like grub. This seems to be very modern and functional software, but it's not all that easy to use. There are some installation instructions, they're rather technical.
Note that the rEFIt page on Myths and Facts About Intel Macs says that you won't be able to use accelerated graphics when using a straight EFI boot, you need to use rEFIt for that.
I think this is the only one. Not 100% sure though.
Grub is also EFI aware.
You may find more information here:-
http://www.insanelymac.com/forum/index.php?showtopic=85508
Personally I would use Grub if possible.
Considering the amount of trouble I had getting my PC to boot from GPT partitions and the lack of documentation regarding EFI/GPT and Grub/Lilo I would say you are going to have a few hours banging your head against a brick wall before you are successful. Best of luck with it.