I'm using Mplus also, so far so good.
Actually this 3 use excel force product, so the result almost the same, just their Customer Service different.

If you planning to trade overseas Market, then Hong Leong will be good.

This is very true IF you know what you are doing. Minimal help from the brokers and the cheapest you can find is AmeSec now. BUT if you need guidance and hand holding, then you need to find a broker that can provide this. In this case, you will need to pay more because now service is better and guidance is also better. In this context, not many broker out there can do it. Some claim they can do it BUT after you sign the account, they suddenly become quiet.

Base on my personal experience, I have signup account with a few. The only broker that offer excellent service and at the same time affordable rate is still Hong Leong eBroking.