I don''t mind "matchy" things, but I think the first invitation looks lovely from the outside...do you have a picture of what it looks like on the inside?
I think they are both very elegant looking...it just depends on what look you are going for.
I actually think the one you posted with the vellum is a bit more formal and elegant, and seems very fitting for a church wedding. Are your colors turquoise and black or black and cream or a combination of the three?
I was in a turquoise and brown wedding last year...it was lovely!
With those being your colors, I actually really like the matching cards and std''s, but I am a matchy kind of gal, but maybe some others who don''t care for matching things will chime in and give you their thoughts, as well.