JS template engines with Rails... opinions?

I am considering going the route of javascript templates for my app, and trying to determine the negatives to doing this. The primary reasons I am looking at this:

  1. Rails 3 + coffeescript is amazing and I see going in a more object oriented direction with js now. That lends to passing data to my app via json objects, at least in the case I am currently looking at.

  2. I have started using Jasmine + jasmine-jquery which allows fixtures. In desire to remain DRY and as minimalist as possible, using js templates looks promising as in essence my ‘view’ will be contained in the js itself and easily passable to jasmine-jquery for testing, which goes pretty far from removing the need for me to run long selenium tests. Once I want to test any rendered views, this method falls apart unless I can render them and attach to the Jasmine spec. Pivotal does have a solution to this but to me this is more of a work-around than a close to the road approach (http://pivotallabs.com/users/jb/blog/articles/1152-javascripttests-bind-reality-).

However, it seems the cost (other than a learning curve), is the loss of the benefits that Rails view rendering provides, such as all the helpers, etc. This is what is good about Pivotal’s approach. Not excited at all to go back to manually rendering and maintaining select boxes, for example. Is there a way to keep some benefit of helpers but going this route, but perhaps in another js library???

So… if anyone has experience or comments would love to hear. Any drawbacks to going this route with Rails – confirmation of what I write above or other problems I have not thought of? Also, from what I see jQote2 is the fastest out there… anyone using?