My experience with both of them were pretty similar, it's like choosing between red and green grapes. It depends on your flavour.
I saw both of them twice in 2017 and had a positive experience.
Instead of my overall experience, I will break down some key observations I remembered.
Observations before play--- Emma tends to escort and tour the country more frequently... Sophie tends to escort occasionally and when she does, she normally prefers her regulars. If she decides to see new clients, she tends to do so only in Coventry.
--- Emma tends to use hotels more... Sophie tends to use apartments more.
--- Their boobs were almost the same size... Sophie's looked rounder and bouncier... Emma's looked heavier and fuller
--- Sophies's boobs were harder... Emma's were softer and squishier
--- Emma's boobs does look scarred and wonky on-screen like a botched boobjob. But when I saw her, they looked a lot better. The scars were still there, but it wasn't as obvious (which was a rather pleasant surprise)
--- In terms of personality, both of them were friendly, but Emma was more talkative and tends to warm up to you faster than Sophie.
Observations during playDirty talkDuring play, Sophie made more sounds than Emma and dirty talks a lot more too. If you enjoy dirty talk during sex, she's your girl.
Eye contactDuring play, Sophie maintained a stronger eye contact, she will normally gaze at you seductively while licking her lips. She really knows how to tease.
Titsucking and TitplayI preferred sucking and playing with Emma's tits. Emma was also more keen to put her tits and nipples in my mouth during play. This was particularly enyoyable in cowgirl.
TitfuckingBoth of them gave a good titfuck... But I enjoyed Sophie's more. Sophie's tits are made for fucking, and with some oil to lubricate that deep cleavage, it felt like heaven.
Doggy styleSophie is curvier in the hips and has a bigger ass too. Her ass is fake though, but they looked better in doggy than Emma's.
Cowgirl styleEmma's cowgirl was phenomenal. She absolutely aced out Sophie in this area.
Energy during sexEmma was generally more animated during sex than Sophie. She also tends to thrust harder and faster... Sophie took it easy and went at a slow steady pace, occasionally increasing the tempo to match mine.
GFE and PSESophie seemed to be more suited for a GFE experience... while Emma seemed to lean towards PSE. (This is subjective and YMMV)
Personally, if they charged the same rates, I'd prefer to see Emma more as I had better vibes with her.
But given their current rates, Sophie is a better VFM IMO. She may even give you a better overall experience.
So here you go, mix and match, and choose your pick