I'm currently sitting at #6 in the Psylocke PvP, just having crossed 500 to get a Ms Marvel cover. I'm hoping to sit in the Top 20 when all said and done and I'll be happy.
I want to dig into the Mystique event, but I don't have Lady Thor nor Beast, so I'm stuck running across the same levels till they are exhausted of points over and over again. I think currently I'm Top 100 in the over all R&G event and in the top 150 of Psylocke, but psylocke is kicking my ass w/ 2k-4k damage moves.
I swear this game cheats sometimes too. Computer just suddenly has all the colors they need to do that move I've been blocking them from, even though I've been monitoring their color count.
The thing that makes things nasty in PvE when it comes to computer color count is the goon mobs. Sience they don't match tiles, they generate AP every turn that they use to power their countdown tiles. However that AP can also be used by the other character in the group to trigger their abilities. Thats why for example Doom matched with goons that generate Black can be so deadly because he is able to trigger Summon Demons regularly off the generated black, even if they aren't matching it themselves. They are doing that a lot in this Rocket and Groot event with both Doom and Mystique.
As far as what people are saying in here, focusing on characters is exactly what you want to do. If you have a good character that you are close to having max covers for, you want to focus on that character, level them up and dont worry about the rest. If you need them for an event they will likely be buffed which will help you anyway. Also if you buy Hero Points, you don't want to waste them on tokens or cover packs unless you have covers you need but don't have. Once you have all the covers for a character you want to level, the better value is to use the Hero Points to buy the covers for that character directly, in the case of 3* characters it is 1250 HP to buy one cover.
To me the best characters to push for at the 3* level are Thor, Black Panther, Punisher, Daken, and maybe Magneto, Human Torch, and Sentry. Rocket and Groot seem like they will be a great character as well, but we will have to wait and see how they play out. I know a lot of people really like Patch, but I am not a big fan of the double edged sword nature of his abilities. If you go off with Patch and don't get an immediate kill or aren't able to eliminate most of the opponents strikes on that first turn, then you could take as much damage as you give. I would consider him stronger if Loki was a more viable character because you could save up, trigger Berzerker Rage, then trigger Loki's ability to turn the enemy strike tiles into protect tiles for you. Sadly Loki just isn't a viable character to use, and his spot on your team would exist solely for that usage.
If you have good covers for XForce at the 4* level how you level him is up to your playstyle. If you do almost only PvP, I would level him all the way to 270. If you are like me and mostly do PvE, you don't want to go much higher than 180 because it will affect your scaling in the event.
Obviously opinions on the matters of what characters are great to have will vary, these are just my thoughts.