I'm thinking of upgrading my DSLR?

I currently have a Nikon D40, and I'm not unhappy with the results, its just that I have been borrowing cameras from my photo studio at school, and I'm happier with those results. My only hesitance, is to make the switch to a Canon… I'm looking into a Canon Rebel EOS T3i, which has the flip and tilt screen, and video capability. Most nikon cameras with those capablities are really expensive and I don't have that kind of money… So can anyone tell me if it is worth it to make the switch?

It really is your choice. You are not only upgrading for the tilt screen but T3i is also newer camera. I think you would like the switch to Canon since their usability is a tad better than Nikons.

Kelly, you did not mention if you have an investment in extra lenses? But if you are thinking about a change. Now is the time to do it before you collect more Nikon equipment. I really question that you are unhappy with the results of your Nikon D40. You did not elaborate what you didn't like about Nikon and what you like about the Canon.
Another question I have is: are you using the camera at it maximum quality or resolution setting?
What ISO are you using?
IF you are using a low ISO such as ISO 125-to-ISO 200 and a high f/stop like f/8, or f/11, or f/16
If you are shooting like the above two lines of info you should be getting great results. But remember 4x6 prints are not the size to judge by. I prefer 11x14's as a rule.
IF you can find fault with any item I have mentioned then maybe a change to Canon is warranted. But if it is just because of the flip screen, remember you can purchase a viewfinder attachment that allows you to look down and thru your viewfinder and accomplish the same thing.
I just bring all this up as it seems you will take a beating money wise.

The Nikon D5100 should be very competitive in price with the T3i. It has processor correction of chromatic aberration. Canon does not introduce that until the T4i.
The T3i may have more video features.
Here are some review that compare the D5100 and T3i.
http://www.cameralabs.com/reviews/Canon_EOS_Rebel_T3i_600D_vs_Nikon_D5100_comparison/
http://www.cameralabs.com/reviews/Nikon_D5100/

You're just getting lucky. Whatever camera you use, you should get the same results. Picture quality depends on user skill. The camera is only a tool. What you are feeling right now is most probably a better handling experience with the Canon. That alone is enough reason to jump ship.

You are moving from one OK camera to just another OK camera. Don't get too swept up by things like a swivel LCD. Sure they can be useful, but what's most useful is better image quality, or really a better image sensor.

If you move from the Nikon D40 to the Canon T3i are you getting a better image sensor? Not really.

Cameras with a much better image sensor should be what you go for, like a Pentax K 30 is huge jump in image sensor performance, it costs 799 when it's not on sale. So keep your current camera for now, keep saving or get a used Nikon D5100, that image sensor is really good too.