Hi,
As an owner of both "similar" guns (an aluminum-framed Kimber Ultra CDP 1911 with an extreme meltdown package) and a very nice 1964 S&W Model 36 (a true classic) . . . and since I've carried them both as a CCW weapon, I'll give my impressions.
The S&W will be more reliable. 3" length 1911 pistols have a notorious reputation for being unreliable until you run 500 rounds through the tube. My Kimber has been extremely reliable . . . then again . . . it was a $1000+ gun back in 2000. OTOH, the Springfield does not have a sterling reputation for reliability out of the box. Then again, some folks have gotten stung with Kimbers through the years too in the short barrel lengths. All being said, I would avoid the bare bones Springfield to protect your life . . . until you factor in the costs of 500 rounds of ammo and a couple of possible returns to the factory.
The S&W M36 though is an incredibly reliable weapon, and always has been. It will also weigh less than the Mil-Spec. My Kimber (being an aluminum frame version) weighs the same as my M36.
Both guns are about the same size but . . . the Smith J-frame revolvers are also easier to conceal with their round butt grips and just a small area in their middles that are wider. That type of shape simply disappears . . . in the pocket or in an IWB holster!
Here's a profile of the Kimber alongside the M36's "twin" . . . the aluminum-framed M37 "Airweight" . . . my ALWAYS CCW gun!
MY RECOMMENDATION . . .
Consider an "Airweight" version of the Model 36 . . . either the 37 or 637 (hammer version), or the DAO "hammerless" version (442/642) or the Bodyguard Airweight and I think you'll be much happier!
My first CCW guns were steel framed guns . . . a 3" barreled Model 65 .357 S&W revolver and a 5" Colt Combat Elite .45ACP. Sadly, they sometimes were NOT worn all the time because you can't always wear heavy guns all the time!!! What's the use in carrying if you don't have it with you when that bad surprise happens and you need it!!!
My M37 was in my little front pocket holster ALL DAY today, as I worked in the yard, including fixing a mower and mowing the yard plus going to the store for things . . . and walking the dog before midnight. THAT'S what I've learned is MOST important.
I back up that M37 with various heavier handguns (weight, capacity and punch), and they are ALSO worn when my outfit can allow. BUT . . . that M37 is ALWAYS there! At about 15 oz. (vs. about 23 for a steel framed M36), believe me, after first carrying the M36, I truly appreciate the greater ease in carrying the M37 concealed. Hope this helps!