I didn't know I needed to shell out that much money in order to be serious about carrying a pistol in the event that I needed one to defend myself.
Either you don't get it or the post wasn't written for you. You can carry what you want and be comfortable with whatever skill level you are at.
For those that use these as tools and wear them out and use and abuse them daily, having a couple isn't a bad idea. There aren't many people that do this, and most cops don't either. Before the industry started attracting and hiring hotheads, idiots, and wannabe commandos, most cops would carry a pistol and only draw it to qualify or use it. Lots of pistols with holster wear and brand new inside for sale back in the 90's...
On the other hand, I've worn out more than a few M4 rifles, various parts, etc. When I break one, it feels good to reach and grab a similar weapon until my favorite is back in service. Also, as a civvie now, I may break a part and have to wait until I find a new one... Nice to know I can just grab the next best rifle and use that.
For carry, I only carry Glocks. I find it doesn't matter much what kind you carry, the controls and all are identical. Just practice a lot with whatever you get. The G27 would be my recommendation, I have one and I use a G22 mag for reloads. The little +1 for the grips work well too, give you the pinkie spot. I like that, so does my wife, that is her pet peeve. Then the G27 becomes a fine BUG AND a fine carry piece.
You'd be hard pressed to make a bad decision in that respect. Get a G27, try it out, if you don't like it, either keep it as a BUG only or sell/trade for what you do want. You'll get LEO prices and be able to do this and break even, if not come out on top, if you decide you don't want it and want to sell it.
I agree, you should carry the same kind of pistol daily. That is very good advice. I just don't agree they have to be identical models. That goes a little too far. The G27 is great for CCW, the G23 if you just don't want the subcompact.
But you could even get a different calibre and still be okay as far as reciprocation of training goes... A 9mm would be okay. But you would lose the magazine compatibility unless you stick with the same calibre.