as a budget 40" samsung 4k owner i'd say stick with what you got for another year .... as has been pointed out your tv is fairly new ... I got mine as I factored in sale of other tv - cost of new tv- and sale price of time I bought for a resale in 12 months as i'll probably upgrade ... which means my £408 Sammy 4k will end up costing me about nothing.
I'm enjoying Netflix at 4k , but the current tradeoff is the motion blur is not great ... It seems the first wave of 4k blu ray players are going to be about £1500+ so that puts me out of the market for now , but in 12 months I should be able to go the whole hog .. If your ok with just having Netflix then maybe its worth it .....up to you