From the experience of 2-queuing at supreme (lost global due to rank decay) when my friend only wants to queue MM:
Not so much the cheaters (although you never know for sure if you get walled, but calling cheats or thinking too much about that shit is a sign of being bad, imo) but the overall quality of teammates has decreased a lot even at decent trust factor levels.
The enemies you notice they do some really silly shit most of the time, even though 80% of the time they're sweaty stacks (in faceit at least you get balanced party members) or will cry about cheating after losing two rounds in a row XD
The last nail in the coffin is probably the last update removing the bot in 4v5 scenarios, which makes the game completely unplayable. Earlier today a dude left my faceit game after 2 single rounds and we somehow managed to win 16-14, in MM we'd been better off resigning after the 3 minutes.