I prefer the old popular ones in the market. Another way to find out if an exchanger is scam or not is from what they promise in return. Some of them will claim that if you deposit $100, you will $10,000 in a week. Wow, what type of organization would give such an amount? It’s a SCAAAMMM!!!!!!
Most people who have fallen victim are always the ones who blindly invest in a project without checking out if they are qualified or not. Have you checked the team, do they have a product, do they have any past achievements, do they have what to look forward to regarding development ? All these are the questions you need to always ask.
To be honest i actually check all of those you mentioned above but unfortunately i have Still been scammed on the past. that is why i can say that it is really hard to find out if a coin or crypto is a scam. but i now learned my lesson , that is why i didnt invest immediately to an unknown coin even if the specs is good or the supply is low. i now only focus to bitcoin and etherium because im confident that my invested capital wont be wasted.