The JIFP is a nice product (I have checked it out myself) but it a major issue when using it away from home.
The typical data transfer between your PC (on which the Jepp JIFP client software is installed, so this isn't an internet cafe option) is a lot of megabytes per flight planning session, so broadband is essential. If you are travelling, you have to bring your laptop, with wifi or you have to find some place (an internet cafe, perhaps) that will let you plug an ethernet cable into it.
The actual user interface is virtually identical to Flitestar, which while being a lot more powerful than Navbox (and indeed I use Flitestar IFR myself for airways flight planning) doesn't even begin to compare with Navbox on the usability front.
It's readily apparent what Jepp did - the JIFP client is a virtually unmodified Flitestar and the internet connection accesses the remote database (instead of accessing the ex-CD database which the standard Flitestar product does). That's why there is so much data being transferred for each user operation.
Jepp are going the right way though. What they need to do is offer approach plates (i.e. Jeppview) in this way. The entry cost of JV3 is far too high for private pilots.
Navbox Pro is cheap - around £60 and that includes the updates for the year.