Don't worry about what others say about her if you enjoy the champion.
If you want to know if the value is worth it, just compare these two numbers:
Her RP unlock price + the sale price of her skin (975RP+487RP= 1462RP)
The off-sale price of her skin (975RP)
If you're looking to save money/Riot Points, you're better off waiting. However, if you really truly desperately want to play her now, you have to ask yourself how much that 500RP is worth vs. waiting until you've saved up the IP necessary and perhaps grabbing another skin when it goes on sale.
In my opinion, save up your IP and see if your taste is still the same when you actually unlock her.