[Esfirius]

Hi!
I've got an Iphone with Omni on it, but I don't have an Ipad or a Macbook, being a PC user. So a question to you guys - is Omni on Iphone sufficient as a GTD system on its own? To me more precise - does having both an Iphone and Ipad/Mac Omnifocus make you seriously more effective at GTD then having just an Iphone app?

Thanks!