Hi Runedog
As an ex drummer myself i am sure you are going to love the Ketron drum sound's and patterns.
To my ears they are without doubt some of the best in the business. Try to listen to the original SD1 demos, particularly the Ac Drummer demo.
As a long term SD1 player even to this day when i hear a particular fill i think that is exactly what i would have played.
As for the choice between the SD1plus or the SD5, i have had no experience with the SD5 but if it were me and i was going to be gigging a lot i would choose the SD1+, if it's for the house it would be the SD5 but as always try them both first.
Hope that helps a bit
Cheers
Sandy