[SkyMarshal]

>Not to mention that these frameworks undergo alot more extensive testing than an average developers code will ever go through. By using a framework you benefit from not having to go through the pain of dealing with all the different browser models and quirks that every version introduces or takes away.

This is particularly what I value in open source frameworks - the hundreds, thousands, tens of thousands, maybe even million of man-hours that have gone into debugging edge cases, cross-browserifying, and finding security holes, stuff I would never be able to replicate on my own in any reasonable time frame. Especially the latter, given the security situation on the internet these days.

My SOP is, stand on the shoulders of giants, unless there's a particular requirement that precludes doing so. Such requirements are rare, most client work actively benefits from use of a framework.