Yes, it seems that it is the 3550. The 355x/455x drives have mature firmware that makes the most of them. Crossflashing to 4551 is another bonus (if you don't want to crossflash and you are interested in labelflash, you might consider buying the 4551)
The more modern 457x series burn worse than the 355x/455x at the moment. Maybe its the firmware, maybe not; time will tell.