Advantages: 1) Ease of use 2) organization (don't have a pile of magazines in your house 3)archive your magazines longer 3) awesome visuals 4) If you a print subscriber many magazine vendors give you the ipad edition for free.
Disadvantages: 1) Its difficult to find magazines in the Apple Store 2) Not all magazines have the same navigation 3) Some magazine can become to gimmicky 4) individual magazines can be expensive.