I mirror the opinion of many of the other reviewers here.
First off, I love Penzu. Penzus desktop web version is much better than the app. I love the ability to have more than one journal (which I think is simply a must for any web/app digital journal), I like being able to add photos and tags to the entries, I enjoy the Search function, the one thing I love that I dont see in the app is Rich Text Formatting. Now, like I said, Penzu is great but I am not here to review Penzu as a whole. Im here for their mobile app.
I pay for the Penzu Pro service. The biggest reason is for the cross device syncing. I really love being able to use my iPad and iPhone to put in entries but sometimes, especially when I want to write a more detailed, longer entry, I use the web version. In order for Penzu to sync to all of your devices you must purchase pro and at $20 a year it is a bit more than almost, if not all, of the other journaling services out there. If youre just going to use Penzu on your one iOS device than its not a big deal but if you want to use it on multiple ones there is just no way around this, not that I know of anyway. Just recently I had some trouble with my bank and my card was put on hold. Because of that Penzu was not able to charge and they immediately blocked access on my iPhone. I had to wait a day until I had access to my laptop to be able to even access it. I know it wasnt paid but still its a bit annoying considering apps like Day One allow cross device syncing for free.
The other thing in the app itself is the UI. Its not horrible or unpleasant in any way but if youre a premium paying customer it does leave more to be desired. Ive used Penzu on and off and during that time they have improved the app as far as tagging and search features but the UI needs some help! It just seems tired. Penzu should take a look at Day One or Wonderful Days. Their mobile apps are a little more user friendly and aesthetically pleasant.
The one thing I want the most is Rich Text Formatting!! Penzus desktop web app is awesome. You can change fonts, font size, color, and everything else that comes with RTF and you can even change the look and background of your journals. The mobile app has none of these. It is very straightforward and stripped of features. I would really, really like to see, even if not everything, some rich text features. At least the ability to change font size and style, color, or even just a couple of different "themes" or something like that.
Aesthetics aside its a great app. I dont ever worry about security. Their encryption is top notch. Just dont forget your password. With a good encryption service their really arent very many works arounds. Within the app you can set an app wide PIN that will prompt you when opening the app and you can set PINs or even heavier encryption to your journals individually. That way can have a regular unlocked journal and encrypt a more private journal for your eyes only.
The only thing I would like to see different about security is for Penzu to add Touch ID support. Day One already has this. When opening the app, instead of entering a PIN, you can use Touch ID to open the app. I personally think Touch ID is better, safer, and easier/faster than PINs or passwords.
If youre looking to ditch the pen and paper and start e-journaling then I really suggest you give Penzu a try. Now keep in mind that a lot of the features I mentioned like the encryption, cross device sync, and personalization features are premium only and do not come with the free version. At $20 a year its not too bad but it is more than other apps out there. If youre looking for a free app or something with free cross device sync I suggest giving Day One a try. Especially if you own all iOS devices and a Mac. Day One has a pretty robust Mac app. For the rest of us theres Penzu.
When Penzu adds Rich Text Formatting or at least some of the features that come with it and polishes up the UI I will consider 5 stars.