Those are both older versions of the 5555 series of radios. Though still available from some places it seems........
The latest short case version of the 5555N2 offers many more features and improvements over the Plus & PlusN.
I guess if you want a more traditional CB appearance then go for it; they are certainly good looking radios!
But I put function ahead of form and I'd much rather have the improved noise reduction, quieter receive, and higher power output that the 5555N2 has (I get 65 watts PEP vs. 45 watts PEP from the Plus & PlusN versions).