I can't compare or discuss a deisel because I have no experience with one. I can just say that for the amount I tow I couldn't justify the difference in cost.
However, I can discuss 1/2 ton to 3/4 ton. I've had and towed with both. I had a 2000 1/2 ton with a 5.3 w/3.73 gears. It had a hard time staying in overdrive and seemed very under powered towing my jeep on a flat bed. I had a 2004 2500HD crew cab with a 6.0 & 4.10 gears. Towed great. Rode like shit and the daily around town mileage dropped from 16-17 to 12-13. At the same time I moved to an enclosed trailer for the jeep. Still towed good. But, since I only tow once in a while as compared to driving it every day and alot of out of town business trips, I thought it was not practical.
I went to a 2007 1/2 ton with the Chevy Vortec Max 6.0 & 4.10 gears. Now I have what I consider a perfect tow rig. It still has the power that the HD had but the ride like a 1/2 ton should. It still has a great ride, a 10,000 towing capacity and FAR BETTER BRAKES than the earlier 1/2 ton has. Note, I never am putting any payload in it so I don't need the stiffer springs. The brakes will stop my 20ft enclosed trailer with the jeep in it exceedingly well, even with the trailer brakes turned off. I had an instance while going to the mounds a couple weeks ago where a guy suddenly decided to turn left in front of me. I slammed on the brakes and the antilocks did their job allowing me to swerve around him totally under control. I am a firm believer in equalizer hitches and will always use one. If you've never tried one, you should. It's worth the money.
RE the pic above showing a flipped trailer. Who says it has anything to do with it being a half ton? Was the trailer balanced properly? Equalizer hitch? Electric brake failure? There are a dozen reasons why it may have flipped & none of them have anything to do with the rating of the truck.
Here's a pic of my 2500HD off the road with my trailer. Shit..... maybe it would have saved me if I had a 1 ton dually with a diesel.