In an odd twist, the slower your character, the more points are available to them, meaning people playing for serious scores have no choice but to play as the relatively slow Uncle Beard (what a name!)
The slower the character, the more points they receive for each scenery hit. The breakdown of point values is as follows:
Uncle Beard - 50 points per scenery hit
Ms Charlotte - 20 points per scenery hit
Swift Arnold - 10 points per scenery hit
This makes Uncle Beard a clear favourite as far as score goes, as he can reap the rewards of boss milking etc far more than the other characters. If it's survival you're after, Ms charlotte presents the best dodging speed in the game.
3 - Stage Scoring Tricks:
Suiciding: There are extra points to be had from suiciding immediately when you start the game (crash into the floor) which releases two power ups. These are normally pretty random, as some times you get a weapon and a bomb, as opposed to two weapons (which is preferable). Either way, make sure you power up either the front main shot, rear shot or missiles - and if you're lucky enough not to get given a bomb, any of those two. Then get back to hugging the floor to build points faster.
A Double Suicide is done by experts at the beginning of the stage to immediately bring four power ups onto the screen (the larger your guns the faster they milk the scenery for points.)
Experiment.