Yup - I have the Pro X2 and use it to send images to my iPad. The Eye-Fi app works well enough but I primarily use an app called Photosmith. I don't really use it to view images while I'm shooting, but I do use it to rate my images immediately after shooting which is especially helpful when I'm shooting on location somewhere. I can transfer images to the Photosmith app, do all my culling / rating in Photosmith, then once I get back home I import the RAWs from my CF card into Lightroom and then use Photosmith to do a metadata-only sync of my ratings/flags/etc from the iPad into Lightroom (it merges the metadata from the iPad with the original RAWs in Lightroom). It's a fantastic workflow that's saved me tons of time. For example I was on location with a few other photographers on Saturday, and during the drive back to the studio (I was a passenger in the van) I transferred the images to the iPad and was able to review a couple hundred images and pare them down to the ones I wanted to edit. So when we got back to the studio I was already ready to start editing while the other photographers hadn't even started reviewing their images yet.
You can also use it to keep collections in sync between Lightroom and the iPad, for example if you want to keep images on your iPad to show clients. I can't say enough good things about the Eye-Fi / Photosmith setup. I've actually switched most of my tablet usage over to a Microsoft Surface, but the Eye-Fi/Photosmith workflow is the only reason I even still have an iPad.