I carry a 10mm Glock 20 as my daily carry, usually. I am in a high-risk industry, and while the 10mm doesn't get a lot of love, I do think it's the perfect compromise between power and capacity. Yes, we all know a .44 magnum is more powerful, if you only need 6 rounds, but when you have to constantly think about the types of situations you normally only see in the movies, there really isn't anything that gives you that kind of power where you can carry 46 rounds comfortably. I usually have 2 extra mags in a paddle holster.
If you're used to the shorter grip and you're okay with the capacity, the Glock 29 should do just fine. I would definitely recommend you go rent and shoot one first. The first 10mm I ever shot was a friend's Colt Delta Elite, before I got the Glock, and I fell in love. It was exactly what I was looking for. I was planning on shelling out $1200 for one of my own. It is extremely heavy recoil, which does have an impact on accuracy. Think of it this way: The 10mm is to the 40 S&W what the .357 Magnum is to the .38 Special. The difference here is that automatics absorb some of the recoil with the action, so your accuracy doesn't quite suffer as much. A .40 S&W is basically a 10mm short. You won't get nearly the same power, but you need to decide what situations you anticipate getting caught in to decide if it's overkill.
I bought the Glock 20 almost on a whim, given that it had higher capacity and was on sale for less than half the price of the Colt. I have to tell you... this is one of the most accurate guns I've ever had. Despite the heavy recoil, I literally trust a Glock 10mm with my life. If you're going to go 10, considering price, frame options, capacity, and everything else, Glock is by far my first recommendation.
I would rent one at a shooting range before you buy to decide. Also, remember that a low-power 10mm is still going to be far more powerful than a .40S&W+P, and as far as penetration goes, 9mm is ballistically superior to almost every other (within reason, folks) round on the market. I'd recommend you read up on ballistics of various rounds. They are good for different things.
Also, and I guess this goes without saying, but a fully loaded 10mm is heavy. The Glock 29 would be much lighter than the 20, I imagine, but about the only way to carry it comfortably is in a Blackhawk SERPA paddle holster. That said, I can and do conceal that way, usually with a Hawaiian shirt or other loose article of clothing.
As for the legal aspect, I've never worried about it because of the risk involved in my job and my friends in local law enforcement, but I also wouldn't worry if I was, say, out at the movies or something. An attack on your choice of caliber and ammunition can also be easily diminished by, 'Well, I carry a Glock because that's what the police use...' (standard disclaimer: consult an attorney before saying anything in court, of course).
My usual advice in this situation, if you really can't decide, is to go ahead and buy the gun. If you decide later that you hate it, you can always sell or trade it for something else. Yes, there is a lot of backlash against 10mm, which I really don't understand. It's not the end-all be-all of ammunition. It has specific uses. But while not 'rare' they are rare enough that someone out there will always want one, if you go to sell or trade it.