In the past, I've used both and was never really quite sure what benefit, if any, they brought.
I do know what downsides they have: namely, they annoy users browsing the normal site from a mobile device with a popup that proclaims their existence. The newest tapatalk, from what I've seen, gets even more annoying, with a banner affixed to the top of your board until you dismiss it.
Thoughts? Do the advantages outweigh the disadvantages?
Do you actually use either of these apps yourself?