This is my second Brydge keyboard, my first I used with my Surface Pro G3, it was a huge step up from MS's no travel keyboard pad. My current Surface Pro G7, came bundled with a MS keyboard, so I'm going compare and contrast the MS keyboard with the Brydge 12.3 Pro+. Given my love for my first Brydge keyboard, I was anxious to try they new Brydge 12.3 Pro+.
First weight, the new Bridge Pro+ is lighter than the original, but more than twice the weight of the MS keyboard, but this is not all bad the Brydge balance the Surface's weight so it can be positioned it at any angle, without using the kickstand. You can also use the Brydge detached from the surface (BT connection) so you can position the surface at greater distance (I do this frequently where the surface is about a foot from the keyboard - or in my lap), I can't do this with the MS keyboard, that has to be attached to Surface, and you can't balance it in your lap (too flimsy).
As I said the brydge connects to the Surface via Bluetooth, but to save power the Brydge powers down after a few minutes of non-use. So when you start to use again the first keystroke is lost unless you remember to wake it up by pressing the shift, ctl or fn key first; I use other BT keyboards all the time so I'm accustomed to this, I also have learned to look for backlighting to be on before I start typing. So this a difference but not a big deal to me.
Key travel/key size - a big win for Brydge, all the keys are slightly larger the the MS keyboard, and the key travel is a little longer, it just feels much more natural to type on the Brydge keyboard - no contest.
Backlighting, I love backlighted keyboards, don't know how I got along without one. The Brydge backlight is almost twice as bright as the MS keyboard, and it stays on longer. It's also adjustable low, med, and bright.
Charging, the new keyboard holds a charge about 3 times longer than their original (6mo vs 2mo); Both are plenty long, and when charging the keyboard you can still use it. The MS keyboard does not need charging, but that means their backlighting and keyboard draws power from the Surface. So with the Brydge your Surface will last longer on batteries.
Trackpad, this is an area the MS keyboard has improved the most. The MS trackpad is very good, but the Brydge trackpad, is slightly larger, and even more accurate, 100% of trackpad is responsive, the edges of the MS trackpad, may or may not do what you would expect.
Protection, the Brydge is made of aluminum, it much stronger than the "Fabric"/plastic MS keyboard. It also heavier, which may, be a negative to some. I'd also have to call the Brydge keyboard is "prettier" the construction is excellent, it match's the Surface's high quality appearance. The MS keyboard, still looks/feels like an afterthought.
One ding (star) against the new Brydge 12.3 Pro+ keyboard with my MS Surface 7, it pulls off the hinges pretty easily. With my old Brydge I could lift the surface and the Brydge keyboard stay connected to the hinges. If I do the same with my new Brydge keyboard attached the Surface pulls out of the hinges. Their original had multiple silicone inserts for the different thickness of the different Generations of MS Surfaces. There is not that much difference between the G4-G7 but there is some, I wish the Surface did not separate as easily as it does.
Overall the Brydge is a much better keyboard, in almost every way than the MS keyword. If I had to buy either a MS keyboard or a Brydge the cost/performance difference makes this an easy decision - Brydge wins. Except for staying connected to the surface, when lifting the screen, it's nearly perfect.