Hi uxo, and thanks KF for bumping this thread! 
Well when comparing both you need to take into account your personal preferences - you're leaning more towards the Oh! Rabbit and I don't blame you! I have the slimline Oh! Rabbit and although it is very small it's nice and powerful for its size.
Oh! Rabbit Slimline - Waterproof, 3 ear speeds and four ear patterns, made of silicone and has 4 inches of insertable length.
Jessica Rabbit Slimline - Waterproof, 3 ear speeds, no patterns, made of skin safe rubber, 4.75 inches of insertable length.
Both take 3 AAA batteries as well.
Personally I would get the Oh! Rabbit but I already know what it's like
It has speeds and patterns AND it has simpler controls than the Jessica Rabbit. Safer materials too. The Jessica however has a longer shaft.
Let us know what you decide to get! x