Transport under 1500 new or used

Firstly, I would strongly recommend that you do not buy anything w/o a rite of return or that can easily be re-sold.
I have tried a bunch of different transports (unfortunately nothing on your shortlist) and have found that many can add midrange glare, lack prat, etc. Some of these are transports that others have raved about and I thought they did not sound very good. There are two transports I have tried that sounded great only they had other baggage like excessive RFI radiation.
Every transport I have owned or tried has benefitted to some degree from a good jitter reduction device.
If you can't find anyone around here that has heard a Northstar transport, just think of what it will be like to try and sell it if it stinks.
Also, I have tried a tube dac, thinking it would have a warm sound and found it to be brighter and grainier than my all ss dac. Therefore, I would not scrimp on a transport, thinking you can compensate for it with the dac.

the Theta data 3 is a excellent transport available used for about $900 here but if the transport mechanism fails you could possibly be up the Creek without a paddle.

A good tube DAC should not act as a filter or smooth things up. It should be fast open detailed but not hard sounding. Midrange to cry for. The transport is every bit as important as the DAC. I wouldn't look for either one to be a filter of any kind. If they are good they should be musical without any hardness without one to tame the other.

Another thought, you might consider the Sony SCD 777ES. Excellent transport. Sacd playback would simply be a bonus.

Try it. You might like it. (especially the quality of sacd. Very close to vinyl. Very close.)

I was pleasantly surprised by its performance as a transport.