Name a feature or function within Gaia. That feature may only work some percentage of the time. If, every time you try to use that feature, it happens to be "having one of it's spells" and either non-functional or super slowed down, it is now 100% failure as far as your use of it is concerned.
But as Williaty wrote above, "Gaia is a frustrating mess software-wise but their map data set just is so far beyond anyone else there's no decent alternatives."