The first aspect of forex broker reviews is to understand that each trading platform for each currency broker is different, and will offer different features. Some companies will provide 'one click dealing', other companies will let you take trades directly from the chart. To a large degree, it will be a matter of preference as to which platform a forex trader will feel comfortable with. However, a diligent forex trader will check how reliable the platform is, particularly during periods of increased market volatility.
An often overlooked factor when doing a forex broker review, is to look at how they deal with slippage and trade execution. This is especially important if you trade the news, when spreads can widen considerably. Some unscrupulous brokers have a tendency to widen them to the extent that it is impossible to trade profitably at the times of news. You can do your research here by opening a demo account first, and to test the platform extensively.
A final aspect of conducting thorough forex broker reviews is to check how they deal with margin calls. As a matter of routine, all brokers allow a trader to trade on margin, with leverage. Whilst this means that you can multiply your profits, it also means that you can take a huge loss if the trade goes against you.
When a trade starts to go against you, some brokers will use this as an excuse to close out your trade, thus creating a significant loss for you, and a gain for your broker. So check beforehand with the broker to ensure that they will deal with this issue fairly, at least by giving you the opportunity to reduce the size of the trade, without closing it out completely.