I've been an avid cyclist and part time bike mechanic for decades. I appreciate that E-Bikes keep people biking past a time or a different kind of riding rather than hang it up. They've come a long way. If you are brand loyal, Specialized makes a great bike. My wife has 2 of them. Most of the components are usually the same across your top tier brands so at that point it really does come down to brand loyalty. Many small manufacturers have come in as start ups and do E-bike specific models. However, in buying from a local shop, a familiar brand (like Specialized) offers support you may not get from a smaller start up. I encourage people to buy from local bike shops when possible and you reap rewards in service and support by doing so while helping local economy.
As far as theft, well, just like anything else, out of sight, out of mind and lock them up. No different really than any other bike. I have bikes that cost close to $5k. A thief, especially at a CG, likely can't tell it from a $300 wal Mart bike. E bikes are heavier and thus likely more difficult to put in a bin or secured somewhere inside. It's problem with all bikes really. There is a company out of Canada that makes a hitch mounted bike shed of sorts. Pretty cool but pricey.
Cheers and keep riding!