For sweetfern, the perfect Reuben sandwich contains corned beef, sauerkraut, Swiss cheese, and Russian dressing, all grilled between two pieces of rye bread. It's a classic combination, and Boston has a number of spots that do it well.
Hounds Luther and Locutus both recommend the Reuben at Sam Lagrassa's in downtown Boston, a popular lunch destination on weekdays (but closed on weekends). North of the river, food_lubber enjoys the version served at Dave's Fresh Pasta, and yumyum thinks All Star Sandwich Bar is worth a try.
South of the river, in Brookline, teezeetoo likes Michael's Deli. "He uses pumpernickel bread and can be grouchy, but he also uses prime quality meat," teezeetoo says of the shop's proprietor. lipoff has been impressed with the corned beef at Rubin's Kosher Deli, but since the restaurant is kosher, there's no cheese on the sandwich.
MC Slim JB recently tried a good Reuben at J.J. Foley's in the South End, made with "surprisingly good quality, thick-cut corned beef." And finally, AaronInBoston likes Zaftigs, especially the new location in Natick, where sandwiches are served with bagel chips and "addictive" liver cream cheese!
Sam Lagrassa's [Downtown Crossing]
44 Province Street, Boston
Dave's Fresh Pasta [Somerville]
81 Holland Street, Somerville
All Star Sandwich Bar [Inman Square]
1245 Cambridge Street, Cambridge
Michael's Deli [Brookline]
256 Harvard Street, Brookline
Rubin's Kosher Deli [Brookline]
500 Harvard Avenue, Brookline
J.J. Foley's [South End]
117 E. Berkeley Street, Boston
Zaftigs Delicatessen [MetroWest]
1298 Worcester Street, Natick