Both the dramas are based on time travel. The FLs travel to the past and try to amend and dive into a better future. While LR also focus more significantly on the present showing their story in the present, SYA talks a lot about the past. Also in LR, the FL is not directly already in love with ML, while in SYA she is. There's love triangle as well, but SML isn't strong for either.
There is a very strong message relayed in both the dramas. If you enjoyed one, you'll definately like the other.
I personally liked both. SYA made my heart ache like anything, and legally romance made me ponder a lot.