for the record I have an 1100, a 1500, 870, nova, mag 10, a 100E .... (list of more here) and a browning BT-99. So I am not being biased!
There are things i like about all of them, but by far the best of the lot is the BT-99!
While only a single shot, it is such a fun gun to shoot! The trigger is perfect and the gun has amazing balance. On top of it all it has probably the best fit and finish my lot and the adjustable parts really help with setting up the gun for personal comfort.
As for shooting doubles... slight of hand pro?
jk I use the 100E or the 1100 for doubles, the 100E is a nice side by side with good sights you can find good used ones for a decent price. I agree with shooting a variety of guns before committing your cash, but in my opinion the BT-99 is one of the best buys for shooting clays on the market (period) its also a heap of fun.