Thats a tough call. The SM 6.1 has the advantage of a completely dead cabinet. Both drivers are different, newer Vifa models in the 6.1 that are not necessiarly better. The SM6.1 is slightly more efficient, a factor if you have limited power and/or a large room. Try your question here for more info : http://www.harmonicdiscord.com/forum...p?forum=3&4235
IMO, the SM 6.1 is going to be a better speaker overall. More detail, better clarity, inert cabinet, better speaker efficiency. The downside is it will not be as forgiving as the wood 6.5. You also have a choice of colors with the 6.1. If price isn't a factor, IMO, go with the 6.1s.