Check out Zero One audio - I own the Mercury and love it, as did 6 Moons in their review.
Escient Compared with Transporter or SB3
I have digested much about front ends and almost convinced not to buy traditional CD transport as front end. Instead having Escient automatically rip my CD collection(BIG PLUS) from an old cd changer to FLAC and play through high quality DAC. Is an Escient on par with an SB3 OR Transporter from a sound quality perspective and ease of use.