I bought a Trek mountain bike over 15 yrs ago. It still works well and have no issues. Now that I am older, I find the mountain bike style to be a bit hard on the wrists. You tend to lean your weight on them and mountain bikes ride a bit rough on pavement. You can get different handle bars I just never got around to changing them out. I might go for a different style altogether now because I am mostly a using paved trails. So when selecting your bike, I would really think about whether or not you will be mostly riding on dirt trails or paved. It makes a difference in comfort level.
I suggest going to a bike shop. A real bike shop not a big box store. You want to talk to people that really know bicycles. They can steer you towards a bike that will fit your needs. The store by me sell Kona bikes. They had a vast array of different kinds. I kind of liked the africabike. Still had the knobby style tires but good for paved roads well.
Here is the Kona website to look over. Biking is a lot of fun especially when the scenery is amazing.
konaworld