Here is sort of a review of the main bedliner products.
LINE-X
Standard - Will fade, black only.
Premium - Fade resistant, black only (colors are coming though and will eventually replace Xtra).
Xtra - Fade resistant, used mostly for colors other than black.
Platinum - Fade resistant, any color, 300% tougher than Premium, available July 2013.
Rhino
Tuff Stuff - Will fade, older low pressure product, weakest Rhino product.
Tuff Grip - Will fade, high pressure, stronger than Tuff Stuff.
Hardline - Will fade, typically applied thinner, slightly stronger than Tuff Grip, slightly harder than Tuff Grip.
Solarmax - Fade resistant, not really a Rhino product (it's from Bayer).
Note: Some Rhino dealers will spray an automotive paint on top of the first three products for colors, but you can wear through that topcoat pretty fast.
According to the products' technical data sheets, all of the LINE-X products are stronger than the Rhino products. I can give you specific numbers if you ask me what you want to compare. LINE-X Platinum blows them all away...by a long shot.
Regarding the wheel wells: The LINE-X nationwide warranty does not cover wheel wells, only the truck bed. The individual dealer can warranty the wheel wells for any period he sees appropriate.