Interesting thread. I turn 40 in a few months.
I've had a few back surgeries at L4/L5, with the final one being an L4/L5 lumbar fusion 4 years ago. Doctor has suggested against jogging for exercise as there is too much compression on the spine. I bought a recumbent exercise bike for the basement and started using it daily. Found I really enjoyed it so I decided to buy a bike last year......my first one in 25 years. Ended up with a Cannondale Quick 3 hybrid. Found I only used 1 or 2 gears at most and was getting frustrated with a noisy derariler and a chain that kept popping off. Plus, it had carbon front forks which I manged to ding which concerned me. With my back issues, I didn't want to risk the forks breaking on me.
Sold the bike a few weeks ago and started looking for a CroMo single speed. Since I live in Canada, it's not easy to order the "darling of the forum" the Kilo TT from Bikes Direct.
Locally, there were slim pickings at the LBS, but I did find a Specialized Globe Roll 1 at a bike shop that had some paint defects when they pulled it out of the box. THey offered it to me for 30% off MSRP and it just happened to be my size. I've been riding it daily for the past 10 days and really enjoying it's simplicity. I have it on the SS side of the rear hub as I'm not interested in riding on the fixed cog. It's quiet, simple and forces me to use my legs vs gearing down on slight hills. I have encountered a few steep hills that required me to get off and walk, but I'm fine with that.
Because I wanted a bit more of an upright seating positing, I have the handlebars set up a bit higher and the seat is down quite low (only 2 inches above the seat clamp). It probably looks odd, but it's working for me.
Looking forward to daily rides on it this during the summer. I might add a quick release skewer for the front wheel to make it easier to get in and out of the car. Other than that, I'm happy with the mediocre, stock components that generally come on big brand bikes. I know many on these forums don't like the big branded, mass market overpriced single speed bikes being pumped out as a trend, but they do serve a purpose for people like me who don't have the knowledge and skillset to build their own for less money. Also, I'm so new to this that premium components would be wasted on me as I probably wouldn't be able to tell the difference.