I've got several platinum/titanium/signature cards. There are only a few basic things to look at .
1. Interest rate - High= bad Low=good (I've got a couple that run about 7% for purchases)
2.Interest calculation - Most of the companies these days use the average of two billing cycles for interest calculation. Just pay it off every month.
3. Grace period - 20 to 30 days is the norm
4. Perks - Your lexus card may get you discounts at the dealership.
I don't think there are any really outstanding differences between most cards. If your credit score sux, plan on paying a high rate. If it's good, you'll get loads of offers. I get one or two every day. Most of them are 0% for a year on balance transfers with no fee. Last time i checked, my credit was in the 800s, but i make a lot of money and have almost zero debt.