I agree with Miss Krys. Vernis as a type of leather needs a lot of care, the coating can become cloudy over time and for lighter colours, it is known to develop a yellow tint. The lighter colours are also prone to colour transfer and you can never clean vernis, nor can a professional ever repair damaged vernis. Scuff on vernis also look much worse than on other natural finish. Creases also don't fare well and over time can develop cracks... I love vernis and I have found vernis bags to hold their shapes well and generally be less prone to minor scratches and with care will last a life time.
I think the best advice to give anyone new to luxury bags is to think about their lifestyle and what they look for in a bag as well as do lots of research on other styles and looks if they haven't already. The Rossmore can be a very versatile bag though very small (it is a clutch) and I would suggest looking at an additional strap to wear cross body if that's a favorite style.
I would avoid eBay unless the seller is referenced in TPF. Other trusted sources are:
Fashionphile.com
Portero.com
Vestiairecollective.com