The main difference is the leaf shape and the color of the new growth. I believe 'Eskimo' has heart shaped leaves whereas 'Royal Flush' leaves are more similar to the standard lacunosa. The flowers are similar on these two other than the fact that 'Royal Flush' flowers tend to tinge red/pink for me when grown in indirect sunlight. 'Royal Flush' is a cross between 'Ruby Sue' and 'Snowcaps'. I feel 'Royal Flush' gives you the best of both it's parents. Beautiful burgundy new growth and speckled as well. I do not own 'Eskimo' so I cannot comment on the growth on this one.

-David

This plant was under discussion in a recent thread (link below).

There is more information

here

and

here

and this seller claims Eskimo is a cross between H. krohniana x H. lacunosa 'Royal Flush' - I have NO idea if that claim is true, but it's interesting.

Here is a link that might be useful: H. lacunosa, H. krohniana, Eskimo

Thank you both for your replies.

mayyan

Here is a link with a picture of 'Eskimo'. Hmm, thinking I need this one.

http://www.epiphytica.com/shop/Hoyas/Hoya-lacunosa-snow-heart.jpg

Dee