During the ICO boom days, I usually got into many exchanges all because when a coin is listed in a particular exchange there is no choice but to work in there. And so I encountered many famous and not-so-famous exchanges most of them were CEXs, Today, I am more into Binance but since it got a big problem with my government I shifted to Bybit and Kucoin since I am a big fan of the convenience of the P2P option. Crypto exchanges have evolved through the years after many of them experienced trials and errors and what we are seeing these days are solid CEXs like Binance, Kucoin, OKX, Bybit, MEXC and so much more. Tested by fire and hailstorm, crypto exchanges must do everything in their disposal to remain safe, secure and solid as hackers are always watching them every minute to look for possible weaknesses. Now, the most important thing is never put your coins on deposit on these exchanges and only use them if you are trading something...this is the top number one rule when dealing with CEXs. With the government exerting their regulatory and taxation power, I am sure that the landscape of this industry is going to be changing and I am hoping that we the small crypto players are to be benefitted with the changes.
I've never participated in any ICO event. I think they were very common around 2017-2018. But I preferred airdrops instead then.
I started using P2P on Binance also until they stopped working in my region. So, I mostly use Bitget and Bybit now. While I miss Binance somewhat because at the beginning, my new choices both had low P2P volume or bidders initially. But after P2P became more popular, they started to have high P2P volume, and that's when I started to have issues with some Bybit P2P traders.
I had to stop using the exchange when I had an issue like this guy here:

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So, now I use Bitget only for my P2P and have had no issues to date. I never believed there was a possible scam when using P2P until I experience a situation when I released find without me getting paid, and the user and support did not bother about it. I see this as my fault, but I was forced to stop using the exchange because it was traumatizing.
Despite the scare, I'm still using P2P on the exchange I currently trust, which has provided good service so far. This experience has slowly built some confidence back, and I hope to regain full confidence soon.