I'm 65 and have commuted on a road bike, a mountain bike, a sport tourer and now an LHT. The LHT, while a heavyweight, is the best by far for me.
The long wheelbase makes it stable and comfortable. I load it up quite a bit with lock, laptop, work clothes and shoes, etc., and it can always handle more. I have come to prefer the bar-ends to brifters and downtube shifters.
When I go for weekend rides on a Specialized Roubaix, it gets old at 25 miles, but I can ride the LHT all day long.