I'd recommend the Manley. We had a shoot out several years ago w those 2 phono stages (actually, a Rhea sig w NOS tubes, I believe) along w Doshi Alaap, VAC Ren MK2 and ZYX Artisan. The general outcome was that the Doshi was clearly the best. The VAC Ren, Manley and ZYX were all close seconds. The ZYX and the Manley were both fed to the line stage of the Doshi; the VAC is full function and so it's line stage made for a variable. All three have different features. Final choice between those 3 very much personal taste and system needs. Rhea as a distant third to all 5 listeners.
Source was a Teres/Triplanar/ZYX Uni. Power amp: Doshi-modified Lectron JH-50 6CA7 push-pull. Speakers B&W 802 (maybe D, can't remember).
I think the retail price on the Manley is quite a bit higher than the Rhea. IMO, it's worth it.