Actually, I just realized the download has a mistake (it's auto generated from JavaScriptMVC). The last line, where it says (true) should be replaced with (jQuery).
This has been part of JavaScriptMVC's 3.0 for probably 6 months. 3.0 is probably in about 50 apps already. We've been using a custom version of 1.4.3 (with some bug fixes that landed 2 days ago). I'm in the process of upgrading to 1.4.3 right now (one more bug fix to land).
Also, if you look at the code, you'll see it is almost exactly like curCSS, except it reuses the currentStyle.
So, if you're thinking code size, it's almost 0 difference because this would replace curCSS and curCSS would use this function.
Also, if you look at the code, it' doesn't matter what version of jQuery I am using b/c it doesn't make use of anything other than a variable called jQuery.