The transition from 3* to 4* characters can be much slower than the 2* to 3* transition. It used to take much longer than it does today — in the game now there are many more ways to earn 4* characters than there were when they were initially released, but with the advent of Bonus Heroes in March 2017, the transition changed completely, and then changed a little more in July 2017. The latest twelve 4* characters have higher odds than the older, “Vintage” 4* characters in heroic and legendary tokens, so the length of time to get 13 covers for those characters decreased significantly.
If you are making the 4* transition today, the characters it makes sense to focus on initially are the latest 12. Head on over to the 4* Characters Rankings guide for a rundown of those characters. Basically, there isn’t a bad one in the group, and even when there are characters that aren’t playing well they seem to be getting revamps fairly quickly to address issues (e.g., see the reworks for Riri Williams and Mordo).
3*s become more powerful than 2* champions once they reached 10 covers and level 127… with 4*s it’s similar, where a 10-cover 4* character can be leveled up to 209 and be significantly more powerful than a 3* champion.
You will also want to closely watch the weekly buffed characters. Each week, five 4* characters are buffed, meaning they are boosted to higher levels than their regular levels. If you’ve only experienced buffed 3* characters, you will be pleasantly surprised by buffed 4*s… they are much more powerful with levels, and a weekly boosted 4* generally does double the damage for each of that character’s powers.
If you focus your leveling efforts on the characters that will be buffed soon, you will get some extra powerful characters for that week, and get the most out of your Iso investment for the short term. To see who is up for being boosted soon, check out our Weekly Buffed Characters post.