Riley is for me more naturally good looking as more girl next door type, lucie is more model type if that makes sense. Both are pretty, just depends if you prefer the hot girl next door, or made up model type.
Lucie is slimmer than Riley. Riley is not fat at all, she is a size 12 I would say whereas lucie probably an 8 or 10.
Both are very good service providers and in an ever decreasing circle of quality English girls these two are now must see girls as probably the only genuine reliable English girls around in the whole Midlands. Can't actually think of any others apart from Sophia rose.
If I were to recommend one of the girls for a first time I think I might suggest Riley. She is not as experienced as lucid which I think for a newbie punter is helpful.
Others may disagree though. Personally before a threesome I'd say see both individually, if you are anything like me, threesomes are difficult unless totally relaxed and obviously it will be more relaxing if already seen both before.