I honestly had no problems with any of the Gyms, considering I've power leveled my Empoleon and Alakazam. What I did have major trouble with was the Elite Four and the champion. I nearly lost in the last two battles so many times, but I luckily barely made it through the end on my first shot, mostly because my only good Pokemon I had to rely on was Empoleon and Alakazam; the rest were all "meat shields", lol.