There are some good ones to work with.
Tamiya's are as always a great kit to work with. The three that I would recommend from them are the M4, M4A3, and the M4A3 (105). All are well engineered and go together very well. All suffer from the same major problem and that is that they do not have the lower sponsons filled in, but this is a very easy fix and a template for this fix is available here: http://www.archertransfers.com/WEB%20pictures/ShermanFix.pdf
Dragon also has some excellent Shermans to work with. But they are a little harder to come by as their best ones are OOP at this time. The biggest drawback or plus depending on your abilities are the indy tracks. They can be a little overwhelming depending on your skill levels and experience.
Just one more thing ... seeing as this was posted in a thread about tracks. Many of the Sherman tracks have rubber blocks on them so that would change how I paint and weather them just a little. The above thread describes more the procedure for all steel. The only difference is that I would paint the blocks flat black andn ot apply any rust or steel to them, but weather them with solely with pastels.
Happy Modelling and God Bless
Robert