When I first got back into riding my bike it was a bit of a struggle as I wanted to ride like I did in my late teens/early 20's (I was 45 when I got back on my bike). Once I got some miles in my legs I found my strength coming back fairly quickly. My legs do feel a bit heavy at times, but usually towards the end of the week.
CV fitness wise I'm loads better. I used to be completely blown out at the top of the hill, but now I still have more in the tank. My resting HR has come down to between 54 and 60bpm from 62 to 68bpm before I started. Even if my HR peaks I can normally hold it at that level for enough time to get me up the hill and then once the terrain flattens out it recovers fairly quickly.
I do push myself though. It's only 30 minutes each way, but I treat it like a mini gym session so effectively I'm doing an hour a day of training 5 days a week. I ride down a hill in the morning, across town and up another hill, then it's the reverse of that on the way home. And I try to ride in all weather, although I'm not a massive fan of head winds.
I'm definitely fitter, but in terms of it being easier it essentially allows me to work harder for longer. Having said that the first time I rode to work I was absolutely f*cked by the time I got there. Jelly legs when I got off the bike and I'd not ridden particularly fast either. Now I'm pretty sure I could ride 85% of the route without breaking a sweat if I took it 'easy', and even after a hard ride I can still run up the stairs when I get to work.