raovjay: If you can't listen to them prior to buying, make sure that wherever you buy them, they have a good return policy. Buying speakers in the blind usually leads to unhappiness. I'd also go to whatever stores you have in your area and listen to other bookshelf speakers. One needs to listen to a variety of speakers in order to judge speakers. Who knows, you may find something that you fall in love with.
Yes, I liked the SM-55's balance better than the SM-65's. The SM-65's were heavier on the bass and that masked or overrode some of the mids to a small degree. But that's a personal choice based upon what I like in a speaker. Others will prefer the SM-65. Others still may prefer the SM-45. Neither speaker's highs are what I call great. They are pretty decent, not shrill, but certainly not inspiring, but I didn't expect that in a $600 or $800/pair speaker. All in all, both are easy to listen to speakers and are worth the money.
So did I buy them? No. I was only curious to see how far bookshelf speakers have come. I'm not much of a Def Tech fan, so I was completely surprised that I liked these as much as I did.