There are a lot of exchanges but few of them could be declared as top tier exchange. There are not all the same and you can find some of these top tier exchanges with upside above other competitors. I like using Kucoin for a whole bunch of reasons which I will try to provide. The main reasons are a lot of features.
First of all is worth to mention that KuCoin is one of the best places to trade altcoins, esp. small cap altcoins. If you are looking how to trade with your hidden gems, Kucoin could be the right place for you.
There is a lot of opportunities to take part in airdrops (you can be active on their Twitter which is pretty rolling quickly) and use their Rewards Hub and Candy where you can earn rewards daily. With Reward Hub you are trying to complete tasks to earn free USDT. With Candy you are collecting candyies daily in order to swap them for some fee deduction etc. It is worthy to check their promotions and get some crypto for free (prediction games, etc.). They have also affiliate and refferal system for those who are interested.
There are some classic set of features such as mobile app, derivatives trading (futures, margin), savings (earn or lend), P2P and others.
There also features such as trading bot which I like to use to automate my trading strtegies or you can use spot or futures grid which works fine for trading (one of the primary trading strategies). Moreover you can use the DCA function and keep hodling.
But there are some unique such as KuCoin Win where you can bet and win some cool prizes (the prizes are higher than initial bet). There is ETF or AI portfolio to be rebalanced and diversified and have some complex strategy. This is unique opportunities how to be ahead of herd.
If you are more interested in mining, KuCoin will also provide you with this option. It is the more convenient variant than owning your hardware (you do not need to care about anything - just paying your bills).
As you can see there are a lot of functions to choose from.
KuCoin has its own native token which can be used for reducing fees, take share of the profits of Kucoin and more. The token itself (KCS) is pretty good investment as it surging and is one of the best performer among these types of tokens. KuCoin steped even further and started their own community blockchain (KCC) which is EVM compatible (low fees, hig speed). It can be easily added to your Metamask.
I would definitely recommend to try it alongside your oher main trading venue. There were only rumors recently that they are in troubles but I am giving high probability of potential default.