Assume you mean Xpel. If these are your only two options, that's what I would go with. It is more transparent than 3M, and less stiff therefore easier to stretch around edges. However 3M does provide warranty for the paint underneath which no other product does.

Suntek and Stek films are both preferred over xpel by a premier detailer in my area.

 

I had the XPEL ultimate applied initially and poorly at that. After two years I replaced it with the Suntek at a respected installer. The XPEL was indeed not as clear as the Suntek. Satisfied so far.