I see this question asked repeatedly in this forum. You're highly unlikely to find the correct answer here. Better to ask a kindergarten class.

The answer to your first question is that no coin, in this moment and time, is a "great" investment. Your second question assumes that some coins will go up in value. You should consider that all coins might go down. If you could short the entire market, that could possibly bring the greatest profit.

Look outside into the world and see how many consumers are using cryptocurrencies. Ask yourself which one you would most likely use and where would you use it. If I had to guess, Bitcoin is probably the safest investment. The remaining choices are little more than lottery tickets at present.

Perhaps you can find a coin you like and donate your time and efforts to helping it succeed. That's what is needed.