Well, other big players (including those supported by Zorro today) such as FXCM, Oanda, Interactive Brokers, or ActivTrades are not getting much better scores or comments on FPA. Except Oanda I have considerable experience with all of them and no major problems yet. Did I bother posting that on FPA? Of course not. You may consider the possibility that such platforms are mainly filled by those who had bad experiences (including bad trades - ok, I had those but my faults, of course) and the more customers a broker has the more bad experience can be made. Some smaller brokers might also be posting their own review results (which is easier for them based on the lower number of real reviews).
At least IG are one of the largest CFD brokers in Europe and regulated by the respective authorities in many countries. Systematic fraud should be very difficult under these circumstances. The fact that they are offering spread betting can be rather considered a plus given jcl's test results with binary options on Financial Hacker.
Anyway, of course I don't know. You probably cannot fully trust anyone, neither any brokers nor review platforms, nor forum comments. So you just need to be careful and apply reasonable safety measures such as distributing your capital across multiple brokers & assets, etc and meanwhile focus on facts like trading cost, tradable assets, platforms availability, API capabilities, VPS sponsoring, ...