My two cents:
When I had a 1500, the K1200LT came out and got lots of magazine opinions that it exceeded the 1500 in most catagories. So, I coudn't wait to test ride one. I took one out alone at the dealers and was most impressed.
Then at Americade (1999), I rode one with my wife on board. These BMW rides are the best test ride you will ever take; they really run them fast and hard through the twisites.
The 1200 couldn't hold a match to the 1500 when riding two-up. It just doesn't have the HP or torque for the job.
Now that the 1800 is out, we are back to the Goldwing being the leader of the category. It was named bike of the year in 2001, and is probably still in that position.
This year at Americade I test rode two other Beemers, they are OK, and if Honda went out of business, I might give them a more serious look, but if you want road performance, the 1800 is the answer.
Tires:
The more fun you have on them, the quicker they wear out. The Stock Dunlops are kind of slippery on wet pavement and the front tire will cup quite a bit by 10,000 miles, even if you top them off with the correct PSI every day you ride.
When you buy some Metzlers, you will get better traction and wear. But still, it is up to you, your right hand and right foot that will determine the number of miles. Some folks go slow in a straight line and get 20,000 miles, others ride the bike like it was designed to be ridden and get 7K to 12 K out of a set. At 10,000 miles, you have spent 4¢ per mile for the tires, about the same cost for gasoline.
If you don't get tempted to buy a lot of appearance items, the price of tires becomes a non-issue due to all the money you saved. Bottom line is that YOU get to decide where to spend your money, on function or on shiny stuff.