No offence... but I like the ones Isaac does. More depth in the text and the all over layout and thought.
As for the panthers vs sabres... all it looks like is a tiger that you've used MS Paint to draw some "teeth" on and the colour of the background of the 'tiger/sabre' is a completely different colour to that of the main background colour. And you can see the colour difference in the Panther's background and the main one also. A little more effort could go into the first one.
As for the second one, a bit better but still depth of font could be different. I can tell you used Photoshop on this one as you have smudged the face of the tiger (which I think has been smudged too much).
I was just wondering what made you do this? Do you study Multimedia or anything? Or did you just decide you'd have a crack and make some? Or have clubs come to you and asked?
Please read what I wrote as constructive criticism it's in no way meant to offend you, just a few things that could be improved. All in all just download some font packs, learn some more basics along with some more advanced uses of Photoshop and it's capabilities and then get 'photoshopping' :P