This was mentioned in the SRC thread, but I figured it merits it's own discussion. Especially if the LT is the true replacement since there's no wideband SM in the works.
SMQV
Pros: Slightly Smaller, 250mw option
Cons: Not wideband, Battery compartment paste can (seldomly) be an issue
LT
Pros: Wideband, Assignable switch, IR Port, Simpler battery compartment
Cons: Slightly Larger
Anyone feel free to chime in with their thoughts.
One thing I can't find info on is battery life between the two. When both set at 100mw, is battery life similar? It would be brilliant if Lectro could update this page with info for the LT : http://www.lectrosonics.com/Support/component/com_fsf/Itemid,714/tag,Wireless,%20batteries,%20battery,%20life,%20SM,%20SMd,%20SMQ,%20SMV,%20SMQV/view,faq/