I used to take a single speed bike with the narrow 25mm tires to commute to work, but there of many times when parts of the trail are closed. I sold my single speed, and now I only own an euro bike and a mountain bike. I do not like to use the roads as during rush hours, drivers can be very aggressive, which is why stick to trails. The majority of the route consists of paved roads and some gravel-like trails. I did not want to wear down my knobby mountain bike tires, so I decided to look for some slick/road tires. I did not want skinny looking tires, which is why I purchased the Nimbus 2 Sport, 650B X 2.3 (27.5 X 2.3). The retail price is $29.00 each, but I got them on sale at Bike Barn for $24.95.
Since we are currently under rather rare situation, I have stayed away from group rides so my euro bike is gathering dust right now. I decided to go on a solo 46 ride on the trails on my MTB with the new fat slick tires. I will continue to use my MTB for training as it offers lots of resistance, I am sure my euro bike will feel light as a feather when I ride again. I think the fat slick tires look so cool, and I can tell they roll smoother than the knobby tires. For me, I noticed a 2/3 mile per hour increase.
Obviously these are road tires and are not intended for off road use as they are slick. They do well in light gravel, and offer great cushion on any paved surface.