Very very different soundwise. Soundwise in how it feels/sounds it's probably closer to a snappier Nobel preamp block in Helix world - with a EQ block attached. It doesn't add the crazy amount of fat middy saturation Retro Reel adds. When it overdrives it goes grainy splatty.
Presuming you're not going for the drive sounds the Closest other pedals aiming for a similar thing for bass players would be the Caveman preamp or that Mantle thing. More EQ options than both, cheaper, with less iron in than Mantle.
I still want a Warwick Hellborg preamp, that's the sound of the bit of gear I should never have sold I want to get back too