As much as I want a Taurus 431, and though I've bought used guns online before using only the dealer's description and photos, I'm getting more cautious in my old age and I'm not sure I'm comfortable doing so anymore. So, I may be dropping the 431 (and 445) since my chances of finding one in person are nearly zero. Still, I've wanted one so long, and there is a nice (it seems from the photos and description) blued one on Gunbroker for a good price right now, so maybe.
So, I'm mostly considering the Tracker, the GP100, the S&W 69, or the .44spl Bulldog (probably the On Duty with the Centennial style profile if I go Charter Arms, ugly, but no exposed hammer to snag on anything but with the SA capability unlike the DAO with the bobbed hammer).
Funny how my thoughts on which way to go can change from day to day. I think the M69 has edged out the GP100. The price locally is only about $65 more for the S&W, and while I like that the Ruger is a true 3", I don't think that matters as much in .44spl or .44mag as it would in .357mag and .38spl. The S&W being 2.75" is shorter by enough that it would likely make a difference for concealment and carry convenience (7.8" OAL vs. 8.5"), and lighter, though not likely enough to make a difference (34.4oz vs. 36oz). Though I doubt that I'd ever shoot magnums in this, that extra versatility is nice should I ever change my mind. I'm also a S&W guy, so if I do decide to spend that much, I'd rather get the Smith.
The Tracker is a little bigger (with the 4" barrel, I'd be looking at a 9" OAL, though it is "only" 34oz), however, it is about $290 less than the Ruger and about $350 less than the S&W. Like the S&W, there is no way I'd ever shoot magnums out of a .44mag this small and light, but the versatility would be nice (if nothing else, I know it would handle the heavier "Outdoorsman" loads from Buffalo Bore and similar from Underwood with no trouble, and the self defense SWC-HP would definitely be no problem, but this is probably also true of the .44spl only Ruger).
While I am disappointed in some of the ammo restrictions for the Charter Arms (especially the self defense Buffalo Bore and Underwood SWC-HP), I'd be perfectly happy with Speer Gold Dot or other modern short barrel JHPs (most of the time anyway). Charter Arms, like Taurus, does have a rather hit or miss reputation (though, most people who own one seem to like them). However, like Taurus, it has a good warranty, and unlike Taurus, it has a good reputation for customer service so if I did have trouble I'm sure it would be taken care of quickly. So, the Charter Arms' strengths just keep it on the list. While it isn't that much smaller than the S&W, it may be enough to make a difference (7.32" OAL vs. 7.8" for the S&W), and it is substantially lighter (21oz) which might make practice more limited, but would be terrific for carry. Moreover, the price is absolutely terrific- about $70-80 less than the Taurus, and almost half the price of the Ruger (and for the price of the S&W I could get two Bulldogs and one or two boxes of ammo).
All three of them are nearly tied. I think I'm slightly leaning towards the S&W at this point, but the price and versatility of the .44mag Tracker are interesting (it would probably be 1st if it was the size of the S&W 69), and the price savings and near ideal carry size along with overall decent reputation of the Charter Arms keep it in strong contention.