I would presume the reviews are comparing load times to other handheld devices, not home consoles. But I bet Angry Birds loads fast on the Vita too.

Ok compared to disc how much faster is it or is it the same?

Shouldn't load times be a huge improvement over disc?

Its a design flaw that Sony has invented since the first Playstation. Now all other companies are copying it too.

It's game dependent.

Pretty much, because the bar for a handheld is other handhelds, that is likely why the comparison is made.  I had wondering about it, because the Vita uses carts/cards, just like the DS/3DS, rather than being disk based. 

Most games aren't that much bigger than UMD games though, I can understand if more detailed models and textures have to load.

That video of Marvel vs...is irrelevent, all marvel vs capcom games on all consoles load fast, they are the exception. Fighting games in general on any optical based media still load fast.