depending how much u really wanna invest in your hobby.
Currently Best future proof ballhead are using Arcaswiss type plate. If you looking for something compact and willing to spend up to $400, u can try Markins Q3T with good performance.
Heard that Photoclam (can try XX33XX, something like this) produce good ballhead as well, of cuz Markins are more reliable, consider this is you are on Budget.
FYI good arcaswiss plate are not cheap too... eg. Wimberly universal camera plate cost ard SGD100 now at cathay photo
Actually if you think about it, Photoclam is not all that much cheaper than Markins. If you compare retail pricing, the difference is $100. If you buy Markins off ebay from sellers in Korea, and after you factor in shipping and all. The difference is only around $30-$50. With that kind of difference, I will take Markins over Photoclam anyday.
BTW, I am not using either. I am too cheapo to use such expensive ball heads. Plus, my heaviest set up is around 2KG only. I am still very happy with manfrottos.