I love that it's easy to save articles from my RSS feeds, or even just websites in general! It makes reading so much easier than having all of those tabs open for long periods at once (which is what usually happens when you're browsing).
The only thing about instaPAD as far as functionality goes would be if they made an app like this available with more features/options outside their website itself - but otherwise there really isn't anything bad here either way. You can use any browser-based reader without needing another program installed; no need to download apps onto your phone etc., which saves time by not downloading something extra each month too often.