In what price range do I need to go for a Dac ?

What do you mean by "better?" What aspect of the Simaudio is lacking and what sonic attributes do you want to accentuate? We all value different things, so if Esoteric's sound lights your fire, Audio Note isn't going to cut it, etc.

Not knowing that DAC its really hard for me to say but at about $2k or a little under there are a number of DAC's I would put in the upper echelon such as a Tranquility SE and PDX. The Metrum is about $1K but you need something like an Audiophellio 2 or Off-Ramp to really unlock it and that raises the price to about that level.

Shameless plug - I have a level 1 USB only PDX available for $1.8K if you or anyone is interested:
http://www.lenehanaudio.com.au/index.php/products/pdx-usb-dac.html

I am in Australia though so the cost of getting it to the US where most people seem to be could be high.

Thanks
Bill

I would like to know what would give me everything the Sim does and more, dynamics etc etc.

There is a lot of variety in how DACs sound. You might just need a different flavor of DAC, not necessarily a better or more expensive one. I think the mhdt DACs are very good values and a great place to start to set a baseline to see if more is needed.

If you like your Simaudio CD player you could look at the two higher end Simaudio DAC's.