Apple's Voice Memos has been around since iOS 3, and in iOS 7 it got a new look and a new icon, but no new features. You can record a voice memo, trim it, and email or text it and Voice Memos also supports AirDrop.
It's a good audio recorder, but it's not for the power user. Audio Memos is far more powerful, and it's only US$0.99. Many users will probably end up buying all of the in-app purchases that take the app price to $9.99. If you can pick and choose to get the features you really need, Audio Memos is powerful, inexpensive, and useful.
Like Apple's Voice Memos, the basic Audio Memos app is, well ... basic. It records voice memos, and it supports iCloud, so you can grab your memo from any device signed into your iCloud account. Voice memos can also be emailed to recipients. The app records in the background, so you can record a lecture while checking your email or playing a game if you like. Apple's Voice Memo also does this. When in recording mode, a red bar is visible across the top of your screen. Tap it and you are returned to the Audio Memos. The app also supports selective erase of part of a recording, but no fancy editing or trimming. Even at the basic level of the app, there is a lot of power.
In-app purchases give you the ability to send pictures along with an audio file, to insert audio into a recording, to compress an audio file to make it smaller and there are also trimming options available. All the options can be purchased together as a $9.99 package, saving some money over buying separately.
Or a user could go for Audio Memos Pro, ($9.99) which has all the add-on features of the $0.99 version and all of the in-app additions, and also adds increased security, variable scrubbing speeds and more.
Both apps are easy to use, and share the same GUI. Audio quality is excellent. The iPhone microphone really is good quality, but users rarely get to hear just how good it is. Both apps have extensive and concise built-in help.
Recordings are done in WAV format, which is pretty much universal and PC-friendly. Recording can be triggered by a button, by a voice, or the app can be set to record at a particular time, pretty handy for recording a speech from a podium with an unattended iPhone or iPad.
The basic app will work for casual use. You may want to add some in-app purchases, but if you want the whole Audio Memos experience it makes sense to spring for the Pro version.
I would also recommend that TUAW readers who are interested in audio recording take a look at Dictaphone, a free app that contains many, but not all the features discussed above. The app supports sharing of files, MP3 and WAV recording, external mic support, background recording, and much more. Like Audio Memos, some of the features require an in-app purchase.
All the Audio Memos apps require iOS 5 or greater and they are universal apps. All these apps go well beyond the Apple Voice Memo app, and are worth a look by the serious recordist. I think the differences between the Pro and regular version are a bit fuzzy. I'd like to see the basic app include more features even if it commands a slightly higher price, but something under $9.99 would be reasonable.
If you just want to sample Audio Memos for free, there is a 'lite' version. It places some limits on recording file size and drops features like bookmarks, voice and timer activation, and reduces the sharing options.