I guess I would say that there was a time when Pentax wasn't doing well at all a few years ago, when they were owned by Hoya. Few new products were released and their camera bodies really lagged in some areas. Ricoh purchased them about three years ago and has put out a lot of interesting camera bodies and lenses in the short time since then and it looks like they are planning to release a full frame camera in the fall.
I happen to live in a rural part of the country. The closest camera shops to me are over an hour's drive away. Locally a Walmart stocks a Canon T5 (or something like that) and a Nikon D3200. So, I end up doing my shopping on line. B and H and Adorama both have full line ups of Pentax gear and have excellent service and are quick to take gear back if it has any problems, so that's the direction I usually go.
As to why I use a K3? I have appreciate Pentax ergonomics, the line up of small, tightly constructed lenses, in body shake reduction, and lenses that offer weather sealing for prices that don't break the bank.
Probably the most important thing for you is not to focus on the camera body (although I personally would choose a K3 over a D7100), but on the lenses you would like to buy. Pentax doesn't have a lot of specialty lenses, but they certainly do have an excellent line up in the standard lenses.