That used to be obviously true. Today, it’s obviously true.

The thing is that in between those two sentences lies a huge amount of movement on the Mac and the iPhone versions which went through revisions to become OmniFocus 2. Now OmniFocus 2 for iPad is out and it’s not only regained this ground as the best version, it now really works on its own.

Officially, all three do. There is no requirement to buy OmniFocus 2 for Mac, iPhone and iPad, you can get any of them. Or none, obviously, but you wouldn’t have be missing out on the single best productivity tool I know.

But in practice, it has been that you start with one version and you are drawn to the others. Partly through how useful each one seems, partly because they work best as a set. Or put another way: they don’t work so well on their own.

The Mac edition has always been the closest working on its own. Its problem used to be that it was just hard to use. Hard to grasp, somehow. Now with OmniFocus 2 for Mac that’s gone, that’s completely gone and the app is as improved in ease of use as it is in features. Today I’d argue that the only problem with the Mac one is that it’s necessarily less portable. You need your To Do list with you everywhere you go because it’s through this that you can make best use of an unexpected delay or a chance meeting.

So if you were intending to buy just one version you would look at the iPhone and the iPad editions first.

Rule out the iPhone one. It is very good. I’ve used it directly perhaps ten times today. I’ve added tasks to it via Siri a couple of times. I’ve now used the new Today View maybe seven or eight times. The iPhone version of OmniFocus is very good and I’d call it essential.

However, it doesn’t include the Review feature that the iPad and the Mac one do.

That’s a really important feature and I think a big omission from the iPhone OmniFocus. It’s how you take a step back and go over every task to see what’s on your plate and think about it all. You do that one or more times a week, then you forget stepping back and instead dive in to do things. It keeps you focused but it also keeps you concentrating on what needs to be done now.

Review is in the iPad version. Now with the new edition, so are improved Perspectives. This is a tool to slice up your tasks in myriad ways so that you can see what you can use and what you can do right now.

OmniFocus comes with some baked-in Perspectives such as the Forecast view that shows you what’s on your plate today plus lets you look ahead to tomorrow and the rest of the week. It used to be that you could only create these Perspectives on your Mac but now, there they are, right there, in the iPad version.

I imagine that OmniFocus 2 for iPad lacks some of the power of the Mac one but in my stress-testing today, I’ve not seen any of that.

So I would say that if expense means you can only really get one version of OmniFocus that it should be the iPad one. But I won’t say that. Because you won’t do it. Whichever OmniFocus you buy, you will pretty soon want the set and pretty soon after that you will be buying the lot.

It’s just that today all three versions are genuinely superb.