I had created a free account on the website to have a glimpse of the service before my purchase as there were no mention of the LTD not functioning for existing users. I bought a Tier 1 and redeemed my code. It seemed to work fine. I connected to my services (even thought I could only find 4 from all the ones I'm using). So far so good but my account had not been upgraded to LTD and at the end of my 30 days trial, the account was locked. When I say locked, I mean the only action I can perform is upgrade to the monthly plan (where the 1st plan would cost you 3€/invoice downloaded, limited to 10 invoices). I cannot even contact the support by chat or unregister.
I contacted the support via email and they took almost a week to answer (after 3 emails to 2 different addresses). The answer is "you can't use the LTD with an existing account, follow the AppSumo procedure". Happy to have waited one week to not have even a tiny bit of solution.

Besides my personal story of code redemption, I found the general usage of the website quite annoying. Each time you get your mouse out of the screen you have annoying pop-ups asking for why you're leaving. You cannot do anything, not even see your account information before you've inborded. That's the all philosophy of the website : "do it our way on our schedule" and I don't like it. So you can't see the list of connectors without an account. If you register for a free account, you cannot even delete your account before you've connected some connectors then if your free trial expires you cannot do anything but upgrade, not even unregister.

The website is quite buggy. For example, if you try to connect to any connector and change your mind or for any reason the connection doesn't work, you cannot come back to the last screen, you're left with a full screen popup where the only possibility is to "retry" and the retry doesn't work. You can't even log out, you have to close your tab, erase your cookies from your browser and login again... so don't change your mind or forget your password if you try to connect to any account inside Vuala.

Also, it's super security audited but they don't force https for their login page. I was almost cought on login on a plan http connection. Try it by yourself http://vualapp.com/login

At least, I hope that those bug reports will help Vuala improving their service and that they won't be so controlling with the users in the future.
For me it's a no-no and a refund.