I have shipped through a number of people, but my reccomendations would be DAS, Intercity, or Gold Rush. DAS is good, but they use open trailors with sides. Intercity and Gold Rush only use enclosed trailors. I have shipped F40's, Carrera GT, GT40, 10k mile E30 M3, and all of our Porsches that go back and forth from RPM through Gold Rush. Always on time, always in communication. If your budgetless, I have access to a 'personal' transporter. He only transports one car at a time, or two if you have two that need shipping as his trailer is big enough. Direct, fast, but expensive.
I have also used a few generic companies, Florida Direct, American Auto Shippers, and a few more. My 325is came from California with perfect paint, maybe a week old. When it arrived it had hail damage, scratches, smoking smell, and the driver ripped off the splitter pulling it off. Was about $3500 in damages. I paid for insurance, but they went out of business before my claim was ever filed/issued. Never pressed a lawsuit as I figured if they were out of business, I wouldn't get anything anyways. Stick with the big names. Let me put it to you this way, in all of my experience, you get what you pay for! Also make sure good detailed pictures are taken before transportation if you want to have a chance with insurance companies.
Wes