yes you need a pump, a top and a res.
some of them sold in combinations.
the differences between tops and reservoirs from different brands include, but not limited to, performance, endurance, convenience, versatility, all sorts of visual features.
I'd pick the Singularity Computers one despite the price, mostly because it looks good, great performer, excellent convenience with huge amount of ports and very well thought mounting options. it's the only one I know that allows both direct attached and separate top with res configurations.