I think everyone has different experiences with insurance companies, but I have had great luck with USAA. I switched from State Farm and saved over $400 every 6 months. The State Farm agent wanted to keep me and asked why I was leaving. I told him I was going to USAA and he said, "oh, I can't compete with them". The customer service at USAA is also top notch. I'm sure there are those who have issues, but most of the complaints I read on reviews are from people trying to get something they can't afford (ie, not qualifying for lower rates on loans and insurance because their spending is out of their league).
As for the 2008-2010 F450s. They are a completely different truck than the F350. As said earlier, different axles, different suspension, and I'm not certain, but I think different frame. The stance is the same (regulated by DOT to 8.5 feet or it's oversize). It does sit much higher due to the 19.5inch wheels and heavy duty suspension.
For the 2011s. There are a lot of complaints about 'killing the F450'. I see it as the F350 became the F450. Either way, it's the same frame with different differential and springs. It hauls great and I see no reason to get an F550 to haul an 18,000 lb trailer. Seems like overkill and wasted money on fuel and insurance.
For the 2011 F450 owners, I would stick to your guns on the insurance problem with the F450. Most don't understand the GVWR. The 2008-2010 were commercially insured due to being over 14,000 lb GVRW (14,500 if I remember correctly). This is a magical number from the DOT. The 2011 is 13,050 and you should be able to find an insurance company that will insure it non-commercially. Especially if they insure F350's since it's the same thing. You may have to tell them "IT'S THE SAME TRUCK WITH A DIFFERENT DIFFERENTIAL, IT HAS 50 LBS MORE GVWR COMPARED TO A F350. WHY DON'T YOU UNDERSTAND SILLY PERSON SITTING AT A COMPUTER!" The person on the other end of the phone probably is imagining a big rig. I was asked how I would park it at the house since it's soooooooooo big.
Note: yes, 13,050 is a big drop from the 08's, but you CANNOT compare GVWR. They took a little hit in the payload (around 600-800 lbs if I remember correctly), but they also cut weight on the frame and engine. The difference in towing went from 24,600 lbs in the 10's to 24,400 for the 11. If 200 lbs ruins your day, then get a 550. Again, 4920 lbs is a lot and if you need more, get a 550. And keep in mind that the F350 towing went from the 18,000 lb range in 2010 to the 21,000 lb range in 2011. So, honestly, did they ruin the F450 by making it a F350, or did they make a smart business decision and combine the two onto one assembly line and make improvements across the board (minus a few hundred lbs in the 450). I'd challenge any 08-10 450 to a mileage comparison. I think my bank account will smile a little more than theirs. Well, I guess we'll both be frowning, but if we wanted to not spend money on fuel, we probably would have traded in our man cards (and woman cards) skipped on the truck and trailer and went for a prius!
Second note: For the 2011 6.7 l owners out there, Ford is putting out a free software upgrade that gives 10 more HP and 60 lbft torque!
Putting the 6.7-liter Power Stroke Back on Top with a Power Upgrade