Nice to have a couple of similar offerings from 2 of the major American makers.
When I asked myself this same question back in 2012, I examined both the S&W Bodyguard .380 and the Ruger LCP.
I didn't want the laser, and they weren't making the Bodyguard without the laser at that time.
I was planning for the role of whichever I picked to be used when wearing jeans with tighter & shorter pockets that wouldn't allow me to pocket-holster one of my S&W J-frames. Size mattered.
The Bodyguard had a larger grip profile, which felt fine, but was just enough larger, overall, that I felt the LCP fitted my needs, meaning my tighter pockets, a bit better.
The triggers were a wash, for the most part. The LCP ended up having a smoother and lighter DAO trigger stroke, but it wasn't that big of a deal, since I'm a longtime J-frame DA/DAO shooter.
The LCP's fixed sights were pretty rudimentary, but a couple dabs of some different color paint and nail polish helped quite a bit.
The inherent practical accuracy of the LCP in some assorted drills and qual courses-of-fire was pleasantly surprising, as was its ability to feed, fire and extract/eject an assortment of JHP's I had available.
I've been very pleased with my choice ... but so have other owners I've met of both the Bodyguard .380 and the LCP.
I recently considered ordering one of the newer Bodyguards that have been adopted within the M&P line, and are now made without the integral laser.
However, when it came time to once again compare the attributes and overall sizes of the slightly larger G42, new M&P Bodyguard and a stainless version of the LCP ... I ordered a stainless LCP (to complement my blued one).
If I carried a .380 in a belt holster, I'd probably go for a larger model (G42 or M&P Bodyguard). Since my pockets in some of my jeans remain tight & short, however, the LCP's attributes remain a decent choice,
for me.
You only have to suit yourself. Try to shoot examples of both, using some representative sampling of ammo you'd normally use for defensive purpose, and see which offers
you the best compromise of features and shooting characteristics.
FWIW, a slide's "hold-open" feature in such a diminutive pocket pistol isn't something that figures greatly into
my consideration of desirable features, but that's just
me.