iPad Mini Retina - Buy or wait?

I've an 1.5 year old iPad 4 Retina but never been a fan of its weight and portability. Planning to sell it and buy an iPad Mini Retina instead.

Is it okay to buy it now or wait until September for a new model or buy the same model for a reduced price? I know this is subjective but any opinion is appreciated.

Also, any drawback in going from iPad to Mini?