We use those 4-in-1 Supermicro systems too, but with AMD CPUs. They seemed a much better deal to us and have a few more DIMM slots (= 128MB per node in our ~2-3

We use those 4-in-1 Supermicro systems too, but with AMD CPUs. They seemed a much better deal to us and have a few more DIMM slots (= 128MB per node in our ~2-3 years old boxes). The only issue was the almost-half-length PCIe slot, it's actually 6" instead of 6.6" so you have to be careful when buying PCIe cards (might not be an issue with the Intel version board layouts). We've also invested in a 10gbe infrastructure rather early (we're smaller than etsy traffic-wise) and found it to be very useful for avoiding congestion issues when we need to transfer large files or pull data from a busy Postgres server. As for HP servers, we avoid them since our DL360 D6 reported obscure fan failures when booting with an Intel 10gbe card and we had to buy the (slower) HP NetXen-based cards instead. Supermicro boxes are not that picky and you don't get the feeling that a vendor might be using dirty tricky to lock you in.