6600M Smart SDR version recommendation

Rusty,

You will get a lot of answers and opinions.

Personally, I'd paid the money to up to 3.1.x.  Not only does it help flex but you get latest features.  Even if you don't think Multi-flex will help you there are other improvements in 3.1.x that I think are worthwhile.

Since it is the main stream of development you will also get updates faster I believe, by a little than being on the 2.x line.

It really depends what you plan to do with your new radio. Look at the features in V3 and see if they are what you need. If the features are not important to you at this time, stay with V2 but make sure you have the latest update. All the performance updates in V3 have been also ported into V2.6.2. No need to pay for a version that has nothing you need,,YET. Later, if you want to jump to V3 for what ever reason you can do that anytime.

Rusty - I was in the exact situation you are in now - having recently acquired a mint, 1-owner 6600M (Silent Key estate sale). It was supplied with SSDR Ver 2.6.1 and I updated it to ver. 2.6.2. After getting familiar with using it, I realized that it was one of the finest HF transceivers I ever used, with many desirable features,  and one I was likely going to keep for the long term. I am a single-op ham and don't do any remote work, so sticking with Ver. 2.6.2 would have been fine for my needs. But after deciding that the 6600M was going to be a 'keeper', I ponied up and bought the Ver. 3.x update. I saved many hundreds of dollars buying the 6600M used so I figured paying another $200 for the update wouldn't 'break the bank' and this way I know I have the 'latest and greatest' and I'll be eligible for all the Ver. 3 updates, which will likely me the last Version I'll ever need. Plus it's helping to support Flex, which as a small business trying to survive in this difficult economic climate, gives me a good feeling - very few amateur equipment manufacturers left in the US so I do not want to see Flex go away, like happened to Drake, Ten-Tec, etc. Just some things to think about. Good luck with the 'new' Flex - I've owned a few different SDR rigs in past few years, and I can honestly say that the 6600M is right up there near the top. 

73,
Bob K3AC