I have used both the Happ and Wico/Suzo trackballs, the Happ one is consistently good quality but like all their stuff, because they are a reseller rather than an OEM they are pricey. The Wico ones vary in quality, sometimes they are a bit rattly and sometimes don't spin very well. So send it back if it has either of these problems, or you could try WD40 on the bearings. The ball in the Wico is a bit heavier than the Happ and when running smoothly has a nice feel.
So why don't we sell the Suzo trackballs on our Ultimarc site? Well the Wico ball (which is a Suzo shipped from Holland to the USA) costs $24.99. The SAME ball purchased directly from Suzo in the UK costs the equivalent of $45! So I could get them for a better price from the USA despite them having to be re-shipped back to virtually where they came from! I have had endless moans at Suzo about this, why can they not sell them to us for the same price they sell to Wico? But they are just not interested. I can go down to Suzo easily as they are only 2 miles from here, any time I need a vent! If I get them in the end, I can then weed out any duff ones before shipping out.