Well, I haven't dealt with 1Broker yet. Mostly I trade on cex.io, as I appreciate their security level. Though their coins amount is not very wide, but currently it isn’t a problem for me. 'Cause my favorite coins are placed there and it's enough for me. As any platform, it has several cons, but in my opinion, pros are outweighing negative moments. However, it’s only my point of view, to find more objective opinion you can check reviews about trading platforms. For example, here - https://cryptohoo.com/cex-io-review/ you can find some more info about cex.