As far as I know, there are not many significant differences between professional account and individual one. But I am ready to share some of the aspect:
1) Leverage i up to 1:400
2) Close out level is up to 30%
3) Dedicated account manager
Moreover, there's a very peculiar cash back program, possibility to refer friends and get rewards for that and some other perks.

In my opinion professional account is something that is worth acquiring, even though I believe you should have particular experience. That is the reason why it's called "professional", it's definitely not for rookies and if you are interested in switching on it, then feel free to apply or ask customer support about precise conditions.

Let's start from the beginning and the conditions on your side of the coin - the deposit. Usually, the professional account requires a significant amount of funds to be deposited into your trading account to get access to improved trading conditions. And as I said, the trading terms are in general improved compared to the standard accounts, or in this case the ActivTrades' Individual account type.
With the Professional you will get tighter spreads, or raw spreads as they prefer to call them. Also, you get improved customer service through a dedicated account manager who will be always at your disposal for anything related to your account.