Started with NerdMiner project before I know anything about it. More than sure that S9 will be the next logical step. Need to find a decent suplier in EU and tinker with it - will have time soon.
Discussion
S9 is great to learn on. But for US power, a Loki board to run a single S19 hashboard at 110V is starting to make more sense.
Not sure about best option for EU that already has 220V.