Lump sum, I don't need to spread the cost so I will take the cheaper option. I will get Platinum.
 
I am discounting the obvious big sweatener, AD2 producer for now because AD1 did not really grab me when compaired to my Toontrack and FXPansion stuff.
 
It still looks to me that there are $149 worth of enhancements in Sonar Platinum. The dynamic sends is a nice one. The control bar enhancements look good, MIDI and PRV enhancements are welcome, mix recall could be a major time saver, and there is a new Pro Channel convolution reverb.

I didn't realise Sweetwater were pre selling the download so I've ordered there with their 3 payment plan.

Either way has its perks/drawbacks.  I'm poor-ish, so affordable monthly payments seem tempting.  But neither am I rich, so saving two payments by lump-summing it seems enticing.  With that extra US$39.98 in my pocket I could go to my local zoo and have a hamburger, or I could take an introductory calligraphy class. 

Mod Bod
I haven't seen how the monthly payment thing works.  Is it an automatic credit card withdrawal?

I've got plenty of cash in my Paypal account so I can do a one time payment but the option to back out of the monthly payments if SONAR Platinum doesn't meet expectations when the drum replacement feature is ready is a nice option to have.

 
Hello Dave I think you hit the nail on the head with your last paragraph. To add to that surely having the option or choice is a winner. I am amazed to see so many negatives when what Cake has done is given you the freedom to choose. 
 
All that I am waiting for is to see the reviews once Sonar 2015 is released and subject to those being positive I could well be tempted to take the monthly rental on the basis I can give it a full working trial and opt out after a couple of months if not happy. Seems like a win win situation to me.

Yesterday, I pre ordered Sonar Platinum at http://www.jrrshop.com/cakewalk-sonar-platinum-upgrade-from-sonar-x3-producer for $126.65 (15% discount Group Buy).

Lump sum for me, WHEN it's available to order in the UK 

Lump sum for me too...I am trying to trim down regular payments, not add another one in to the monthly budget...
 

Lump sum. Pay and forget for a year.

Payment plan. My wife has spoken.

After playing with the idea to jump the X4 upgrade,
i came to the conclusion to pay lump sum for the platinum pack
cause I really like ad drums ( three packs included, that´s alone worth the money)
and I like to have a platinum version of my daw software, reminds me of the good old logic days (hihi).
So it´s OK to call me a dinosaur.
regards