is it convenient to make a game with the Platform pre-style
There is no platform pre-style, there's just a behavior that simplifies the creation of a platformer type movement. It works very well, and I would recommend using it if you want a platformer type movement.
Or should I continue using Detectors and stuff like that?
Well, it depends on if and what you need them for. Detectors are used in much every game that exists, it's not like they're a mmf2 specific workaround or anything. Even with the platform behavior, you're still going to need detectors for the more advanced stuff.
I knew that there was disvantages on MMF2 with making games with the Platform predefinied style, but I don't know if it's the same on Construct. What do you recommend me?
Construct is essentially an mmf2 styled game creator with a MUCH better coding system and runtime. And if you're making a platformer, go with the behavior for the base movement engine of your game. The more complicated your game is, the more stuff you'll have to code yourself, and that may or may not involve detectors. And welcome to the community.