I have been using Bumblebee on my Dell Vostro 3750 for about 6 weeks now and have found it reliable and performant. My only niggles are the following:
1.) The need to run or configure optirun prior to the graphics card being initialised. It would be nice if Bumblebee could detect an application making a 3d call and enabling the card automatically.
2.) The fact that my display would cut out whenever Ubuntu 12.04.1 started up. This was recently resolved by discovering that acpi=off fixed the issue which led me to find the following post:
This led to
I updated /etc/default/grub with the following GRUB_CMDLINE_LINUX_DEFAULT="acpi_backlight=vendor"
and ran sudo update-grub. My machine is now working perfectly. Yay.
Bumblebee is an incredibly promising development and I am proud of the work that the team has done. 3 cheers for open source developers and their hard work !