It depends entirely on how long you want the suit and paint job to last. If you are just using it for one con as a throw-away, then yeah, Leak Seal is the way to go.
For long term use, I find Plastidip always ends up peeling. Any bumps or rubs at cons I found to scuff my paint which starts it peeling. It is also hell if you kneel (carpet burn makes it peel, same with dirt from the ground). Then you have a choice of peeling the whole darn Plastidip job off (not fun), or trying to paint over it which makes for ugly lines.
I'm a sucker for a good old fashioned coat of Bondo and some fiberglass mat over the foam. If you are looking to have your suit last forever, it makes it more durable, and then you can just directly spray paint it (fine sand first... it makes the paint stick better). Sure, it takes more sanding and costs a bit more in materials... but if you are building a suit you want to last a very long time... invest. Plus, when you have to repaint, it is cheaper to buy spray paint than more Plastidip.
For long term use, I find Plastidip always ends up peeling. Any bumps or rubs at cons I found to scuff my paint which starts it peeling. It is also hell if you kneel (carpet burn makes it peel, same with dirt from the ground). Then you have a choice of peeling the whole darn Plastidip job off (not fun), or trying to paint over it which makes for ugly lines.
I'm a sucker for a good old fashioned coat of Bondo and some fiberglass mat over the foam. If you are looking to have your suit last forever, it makes it more durable, and then you can just directly spray paint it (fine sand first... it makes the paint stick better). Sure, it takes more sanding and costs a bit more in materials... but if you are building a suit you want to last a very long time... invest. Plus, when you have to repaint, it is cheaper to buy spray paint than more Plastidip.