I'm a little late to this party, but here goes anyway.
My best selling era is WWII (big shock); within that era, The Battle of the Bulge Americans, Germans and the WS winter sets have and continue to sell the best for me, the Hummel has been my best selling vehicle BY FAR, followed closely by the M10.
Next in line are all of the DAK sets (wildly popular), then the entire FOB range. This range has been a sleeper overlooked initially but making up ground with the last batch of releases, all are terrific and the British can be used for multiple displays; far east, Crete, North Africa, Sicily and Italy, etc.
I have also done very well with WS 72 and WS 73, especially WS 73. The new DD sets have been a very good mover for me, DD 78 especially. I've got loads of wargamers as customers and they love DD 81 through 87, can't get enough of them.
No states secrets to hide here; bottom line is I attend over twenty shows per year and you can't beat the shows, people come to shows to buy, buy, buy and I am there to sell, sell, sell. I see very few people walk out of a show with no bags in their hands and see quite afew people go back and forth to their vehicle several times during a show...................
My next best selling era is the Saracens and the Crusaders by a long shot. I consistantly sell these figures at all the shows, move quite a few at every show. They are visually stunning, I think that is why they do so well at the shows, all of the mounted figures are sure fire crowd pleasers.
Napoleonics are in the middle of the pack, I do more than my fair share with them, the Cuirassiers are flying out of here, as are the British Guards figures.
All of the other ranges (AWI, Alamo, ACW, WWI) do well as a group; regarding the ACW and WWI, most of my customers are laying in the weeds to see what comes next, action poses are begging to be done and we all know WWI action poses will be spectacular.