On company philosophy, the trigger lock certainly raises concern. As far as I can tell, at least 90% of shooters dislike it and many absolutely abhor it. Some have even stopped patronizing Smith over it.
Must be why you can't find any S&Ws on shelves anywhere.....folks just ain't buyin' 'em on account of that stupid lock!
In all seriousness, the IL is a non issue. It has no higher of a failure rate or automatic lock-up than any other part in any other model of gun, regardless of manufacture. To most folks that as you state, abhor it and have quit buying S&Ws, it is all about the politics, not anything at all about performance or failure.
I myself prefer a L-Frame for .357 as opposed to a N-Frame and for HD, trail and range a 5'' barrel would be preferred over a 4''. In a holster or sittin' on the table the 1'' of barrel length vs the extra weight would be a wash. The extra velocity, longer sighting plane and the extra weight forward would be the advantage. The one extra round would have no influence what-so-ever.
As I said at the beginning of the response, finding any of the popular S&W models for sale anywhere is a problem and availability may have more influence on your decision than anything. Now is not the best of times to buy a handgun, and many S&Ws, if you can find one, are selling at or above MSRP, something that was highly unusual just a few short months ago.