I just had a very nasty experience with OmniOutliner Pro / Kinkless GTD. It crashed, and despite backups every day and every five minutes I just lost at least a day's worth of notes. As the GTD'ers out there know, GTD requires a trusted system, and I just lost my trust. Here's a breakdown of my breakdown:

• OmniOutliner crashed during the automatic backup. I guess it doesn't cover that situation, because I ended up with the last saved copy.
• I rarely save my kGTD document because it takes far too long (1-2 minutes is my guess). I have been able to deduce that it has been at least a day since my last backup.
• Daily backups are broken. Today is Tuesday. A backup was available from Sunday but the last Monday backup was 8 days ago. It turns out that 'daily' backups are made whenever you sync rather than being made daily as I expected
• I rarely sync, because it also takes too long.

Unfortunately I have not found or built a better alternative to kGTD yet. I have little ill will towards Kinkless, who have created a convenient hack for the GTD community, but it is far from a solid solution.

What really disgusts me, in a more abstract sense, is that when this sort of thing happens to a user, the company will probably never know. And if we continue to use the product they will assume that that means we actually like using the product.