In other words, if you're texting someone from your iPad, then leave it on your desk and walk away with your iPhone, new messages will continue to be delivered only to your iPad. I was unable to figure out how the service determines which device messages are delivered to. At one point I thought it was the last device you sent a message from, but my theory was debunked after sending messages from my iPhone and watching a different device light up as I received replies.
The app simply doesn't work efficiently across multiple devices, which is unfortunate and inexcusable for a communications app in 2014. At the very least it should only allow you to be signed into one device at a time, similar to how BBM handles multiple devices. That way the service would know which device you're currently using and where to deliver new alerts. Sadly, FreeTone does not.
Placing or receiving both text messages and phone calls within the US to another number of the same origin is completely free, though the app makes it confusing to ascertain at first. Even with free calls and messages advertised in the App Store listing, upon first launching the app and seeing references to credits and methods for checking how many credits a call is going to cost made me second-guess the free claim.
With a little digging, I was able to see that most calls and texts are free as promised.
So what are credits? For starters, the only reason you'll need credits is if you plan on calling or messaging someone out of the country. Credits can be earned by watching video ads, completing offers such as installing (and launching certain apps) or watching "premium" videos. The option to purchase credits starting at 99 cents|69p|AU$1.29 (for 40 credits) is also possible through an in-app purchase.
Credits can also be redeemed for sticker packs, sound packages for alerts and color themes through the FreeTone Shop. So basically, aside from long distance, the credits currency is used for cosmetic changes.
In other words, your credit balance is prominently displayed atop your inbox, which is what immediately gave me pause. But while you'll need it for some things, you'll be able to make free texts and calls as advertised.
Ads and more ads
Littered throughout the entire app are ads, randomly appearing inline with messages in a text conversation and other times pretending to be a conversation in your inbox. The frustrating part here is that the ads aren't consistent in when they appear. For example, at one point during testing I went to tap on a conversation only to have it replaced by an ad (and the conversation shifted down in the list) at the last possible second. This resulted in me inadvertently tapping on the ad.
Eliminating ads altogether is possible through in-app purchases. For 99 cents you can remove ads for a month, or $4.99|£2.99|AU$6.49 will banish ads for a year. Nothing is truly free, I suppose, but just be aware that the ads can be pretty aggressive.
The lack of true multiple device support and the occasional hiccups with message delivery make it difficult to justify FreeTone replacing your phone number. In fact, to me, it makes this app a nonstarter.
To make it worse, the ads can get really annoying and employ tricks that have them appear suddenly, so you'll accidentally touch them when you intended to do something else.
While I wouldn't recommend it as a replacement for your regular calling app, FreeTone can still be useful. You can still make calls and send texts if you watch out for the ads and it will be occasionally useful as a secondary number when you don't want your recipient to have your real contact info. But there are plenty of great free apps already that let you send texts, and the headaches in this app just aren't worth the effort.