Sounds like it depends on where you are based, Gdax, as mentioned above, is a better option. I'm looking at buying, but my account is in the UK. Gdax seems to be the better option, but I need to transfer money through to their European account before I can purchase, and that can take up to 4 days. Just investigating another option now that a friend told me about earlier, so I'll be back.
Just something worth mentioning since it seems like we're only discussion Coinbase/Gdax here,
one can easily use any other exchange, depending on your trading volume you might not even need to do KYC, and it doesn't matter where one is located then.
One can simply buy their crypto from Coinbase, and send it over to any other exchange, just so new people know that!
Generally, any exchange handling fiat seem to require KYC right away/early, while those who doesn't handle fiat, only demands it if you reach a certain trading volume.
My personal favorite is huobi.pro. 0.2% fee and
very low withdrawal fees!
They're also #3 on exchange volume(
https://coinmarketcap.com/exchanges/volume/24-hour/).
Binance has 0.1% fee's which I guess is better for trading, but a lot higher withdrawal fees, so if you're looking to get some altcoin, better to use huobi, or some other one which is cheaper for withdrawals!
Both Binance and Huobi lists alot of various cryptos, according to cmc, Binance has 330 and Huobi 230.
GDax is #12 largest by volume and only lists the biggest coins.
although if you're only wanting to trade those and have easy access to withdrawals, then I guess it makes sense!
I only ment to add in some alternatives so people don't get stuck on coinbase.
If you want to purchase using bank card = coinbase is great, and instant, and KYC is instant aswell. I'm not sure how many other exchanges accept bank cards.
with bank transfer it's also very cheap, but slow - and if it works the same with them adding a a few $ on top, it might be better to find a fiat exchange where you can buy 'p2p', depends on your region which one.
by 'p2p' I mean where you atleast can see orders at various prices rather than having to buy for 103%(example figure) current market, not actually p2p!
I guess one also sells for 97% current market