Personally I wouldnt touch a 15k spindle unless all I did was surfacing.
Before we bought our vf2ss I talked in length with the techs at haas about the 15k spindle. the 15k spindle has ceramic bearings any shock will pretty much render them useless. heavy cuts are a nono. for a job shop a 15k spindle isnt worth it. unless you have more than one machine. if this is your only machine get a 12k spindle you can cut more. and yes a minimill will cut really nice with a 1/2 endmill.
Haas reccomended we didnt buy the 15k option for our line of work(ie job shop) and I do a ton of surfacing. but also peck drilling, hog outs etc etc.

geoff is a wizard on mini mills he might chime in unless he is on vacation again .

Delw


Anymachine is worth the highspeed option makes a huge difference in a job shop wether you think you need it or not.