The Big+ probably would have been nice.I'd narrow your choices down to either the 16k or 10K HT.
For a shop only doing aluminum I'd suggest the 16k, but the 10k HT is a beast for a BT30 spindle and will be closer to a 40 taper. Way more torque and comes standard with Dual Contact, although you can get this on the 16k as well. 10k HT is going to be a better job shop/universal spindle and handle larger and longer tools better but I've seen some massive stainless parts done (6"+ thick) on a 16k that I previously wouldn't believe. Honestly, you can't go wrong with either one.
If I were personally buying a Speedio, I'd go 10k HT since I do a mix of materials and I don't care that much about the higher RPM.