I've stuck with Skyforce Unite for about a week and a half. Currently up to world 11, and can grab world 12's map whenever I want to. Still free-to-play, because why would I pay for a simple RPG? Seem to get 12 "mile points" a day and 3'ish medals (ingame currency) for consecutive days of logging in, but after missions/chests/blue squares/level clears, it's probably closer to 40-80 mile points and 10'ish medals. Enough that I do "speed-up" upgrades with tokens whenever I can't be arsed waiting, and repair costs are usually a non-issue, even with skill levelling chewing up the mile points. Cash is similarly not a problem.
About level 45, rank 30'ish (?), with my Ranger/Merchant/Knight apprentice still carrying the team on items/money/picking/scouting when needed. Plus, she's got a 2-star Dolphin bomber thing that is twice as good as any other hunk of junk I'm flying. Dodges damn near everything, has 730AP/480life anyway (soon to be boosted), with a donking big V4 Saturn engine. Plane's level 35 or so, but I'll chuck the next set of eggs at it to get it to lvl 40-45. A worthwhile investment
She out-stats my "main" pilot by miles, so between the plane, all the halfheartedly levelled gubbins, the H2V12 rockets, and whatever else I dump on the thing, most encounters are over in one turn.
If you ever see Air (or Air girl) of sambojin's Valkyries on there as free help, grab her. The lockpicks are nice, but the firepower and resilience are ridiculous.
Turns out virtually anything is good if you drop 10-20 levels of stuff in and mod some items onto it. She did 1332 damage in one attack to a brontosaurus, *and* stalled it on the ground, with a modded 7.7mm vulcan. I was rather impressed, considering that was my first ever rare weapon, that I still use and upgrade to this day
Better stuff is better, but any PoS works if it's levelled and modded halfway decently. So you can stay ahead of the curve regardless of item draws or p2w stuff. Maybe not in arena, but it's not really a dueling RPG anyway.