If you like the model then get it, rules are temporary (and it is an awesome model). How you use it should depend on the type of games you play; casual or competitive.
For casual games this thing is extremely powerful, as BrainCandy stated*. Fielding it as is would probably not be fun for anyone involved. I'd proxy it as a redemptor/venerable/siege/contemptor/howmanytypesofdreaddoyousmurfshaveanyway dread instead.
For competitive games there is no such thing as too much cheese, bring three and bubblewrap with conscripts.
* my local flavor-of-the-month
waac powergamer guy has been chomping at the bit to try one of these with 2x grav bombard since it got its current rules, while never mentioning them before 8th. That should say enough