It’s all down to personal choice, what suits one person may not suit another, just like real pianos.
Pop over to this site http://purgatorycreek.com/ and choose the Digital Piano Shootout, which will allow you to compare all the different VSTi with a Real Steinway.
As to a computer, then choose one that is at least half as good again as the minimum spec suggested by the software.
Hope this helps

Bill