I love ENGL amps but you can't go wrong with the 5150 for a Machine Head type of tone.
Keep in mind your tone also depends on the rest of your rig (fingers/picks/strings/guitar/pickups - Boost Pedal - post-EQ - Cab / Speakers).
This weekend a friend of mine tried his 5150 with an ENGL V30 cab, then Mesa Rectifier V30 cab and finally Krank Eminence cab. The tone was very different from one to another.
I tried with engl 4x12 cab with v30 celestions in it.tried different presence settings:everything from 9 o'clock to 3 o'clock.It does sound good,but somewhat not agressive,i would say massive and fat,but lacking that MH bite and clarity maybe!