Spoilt For Choice - Yiistrap, Yiibooster, Yiiwheels, Yiifoundation, Etc

So, I’ve been looking at ways to jump start the front end effort using Yii and came upon these extensions. I’m a little confused as to which is the latest and the greatest. Also, it further confuses me because some of these are dependent on others. I would help if someone, with some background knowledge could help me understand these.

What baffles me most is this sentence - Wheels is an extension library for the Yiistrap extension.

An extension for an extension?

Here’s what I’ve gathered so far, listed in what I think is the chronological order these were developed in:

[list=1]

[*][font="Courier New"]Yiistrap[/font] - The ultimate Twitter Bootstrap extension for Yii

[*][font=“Courier New”]YiiBooster[/font] - is Yii Bootstrap on 'roids

[*][font="Courier New"]Yiiwheels[/font] - Wheels is an extension library for the Yiistrap extension (It differs from its predecessor, [font="Courier New"]YiiBooster[/font], in that widgets and their assets are isolated in their own folders; which promotes better and easier maintenance. Yiiwheels requires Yiistrap.)

[*][font="Courier New"]yiifoundation[/font] - YiiFoundation is the extension library for ZURB Foundation 4

[/list]