Specialty Catalogs: Michel is used by specialists, but Scott, especially the Scott classic catalog, is actually quite good.
Specialty Albums: Lighthouse is the gold standard, but by far the vast majority of American collectors who collect both Mecklenburg-Schwerin in particular and German States in general use the Scott specialty series pages which is very good.
Expense: Most German States stamps sell for lowish percentages of catalog, especially if a collector is willing to accept a small thin or crease. Nice looking, slightly defective stamps should cost in the 20% of catalog range, and the entire country should be able to be collected for under $500.
Overall Grade:B