My son dropped his phone and cracked the screen.
I spent the longest time on removing the cracked screen. The screen is on tight and the suction cup provided with the kit was NO HELP, even with clear packaging tape covering the screen. However, the site provides very good instructions for removal and replacement...for the most part. If you only buy the screen kit, keep in mind that you will spend extra time transferring the camera, speaker and Home button from the old screen to the new one. This is why it took me longer than expected to finish.
My advice...take your time and don't be in a hurry to finish. Since you are dealing with VERY SMALL and fragile components, don't try to muscle anything loose. Follow the directions and the pictures. I would also recommend keeping the screws with the components you remove and make sure the screws go back into the SAME PLACE you removed them from (VERY IMPORTANT). Don't use the suction cup to remove your cracked screen. I used a razor blade and it fit perfectly between the screen and the bezel. Just be careful to not cut into the bezel with the razor blade. I used the blade to lift the screen enough to get the blue pry tool in then used the pry tool to finish the job. It took me a while to figure that out. Also, since you're dealing with small components, a magnifier and plenty of light would be very helpful.