You see, my two year old Macbook already has an Instant-On technique. When I open the lid, I see my desktop in 2 seconds or less. That probably beats Splashtop. Also, I can then access all my applications rather than a restricted subset. What is this amazing technique, you may wonder? It is simple: ACPI! You see, when you have a frequently used computer with a stable operating system and ACPI support, you can go a long time without rebooting. Basically, the only limits are hardware failures and your need to install security updates. In this case, the boot time does not matter. Sure, it drains a little power, but if you use it more than once a week for a long amount of time, you will have to carry a power cord around anyway. Ultimately, working ACPI support would be a much more viable 'instant-on' technique than Splashtop.
What about viruses? Alright, what about them? Sure, if you use Splashtop, it might be harder for malware to maliciously modify your computer, but if a remote vulnerability or privilege escalation vulnerability is discovered in your software, that vulnerability will remain viable for a long time. There is a tradeoff.
Also, how many people actually use these media-BIOS things anyway? My mother's Dell laptop comes with 'Dell Media Direct', and it has been nothing but a nuisance to her; she sometimes accidentally boots into it and fiddles with it for a few minutes to return to Vista. If Splashtop is used in this fashion, then millions will hate Linux just as much as we do.
Ahhh, the smell of victory!
