noOne knows for sure when Maxwell is going to hit the market, there are rumors that nVidia is going to test Maxwell production soon
http://www.tomshardware.com/news/nvidia ... 25803.html However, these are rumors, rumors to build the traffic for advertisement business all these websites are living from, that's all. So take this 'info' with a grain of salt..
Knowing nVidia they to tend to release products differently, sometimes they put the best first & then the lower end models, sometimes opposite, so even if You will wait for a month or two and buy a piece if it comes..it's a bit of a question what You're going to get in terms of performance withing that architecture - might be the case that You pay extra to be among first one, but month after new card will come..that leaves You not so satisfied..
So to help You a bit, You should decide how much You want to spend & what is top most important thing to You (amount of vRam or performance). Maybe overall value - these are different from user to user as our needs are based on what we do..some will even offer to buy second hand, or older generation new card (if You can find one) to get better value.
When You thee in perspective & take into account things like upgrades (You can buy two cards that might come cheaper now, but one card leaves You some space on Your mobo if You might wish to upgrade Your rig later without trowing out something..), heat/noise (it's one thing to have computer in a studio & other thing to have one in Your apartment)..
Everything is subjective here =) because needs are a bit different from person to person, so without knowing what You do, how You do, why..it's difficult to recommend something. But if You list Your needs by Yourself - You should find the answer fast enough =)
cheers