Fast trax turf ripper tyres- any good?

[Timee80]

i know these are allowed for use in the regionals but have never tried them. Are they any good? they seem to be a fair bit cheaper than schueys and ballistics.
If they work, when should they be used? eg surface, dry/wet
How do they wear compared to the others?
I know you guys who got the first lot of c4.1 kits had them included in the conversion so lots of you must have tried them