We have run a 2005 1770NT 16R30 since it was new.  We have the fertilizer frame and a 600 gallon factory mounted tank on the middle that we run in furrow starter with.  Ours is 3bu boxes which work perfectly fine but I look forward to getting a CCS some day.  I used to worry about weight on the CCS units but with fertilizer tank on ours filled up it's plenty heavy too.  Wing weight transfer should be a standard feature on all planters.  

We have added lots of little goodies over the years.  20/20 SeedSense and RowFlow controlling AgLeader electric clutches has worked absolutely flawlessly.  Whatever you get put on the RK gauge wheel kit immediately, you will not regret that.  As far as the planter goes it has been relatively trouble free.  Frame is rock solid, keep it greased.  I may have to rebuild the wing hinge pins on ours if we keep it much longer, I can see the play in them when turning fast on the headlands.  Have plenty of marker breakaway bolts if you use the markers a lot.  I only broke one all spring but I only use them for headlands now with autosteer.  Spend some time looking over all the hydraulic hoses where they pivot, we have replaced a bunch that rubbed but could have been avoided if we moved them or tied them up better.  I started adding the nylon sleeves to hoses anywhere they can rub.  Protects and looks nice and clean.

The biggest downfalls of ours would be spring downforce(side springs with no adjustment).  I would really try to find one with air bags or at the very least the HD adjustable springs.  I'm contemplating changing ours over to air this winter(buy someones used air bags that put DeltaForce on, there's tons for sale).  We also have the mechanical ground drive seed transmission which works fine but goes through a lot of chains and sprockets if you want to keep then in tip top shape and you can't variable rate population.  The same for our row unit drives, we run chain drives and then a short chain for the clutches so again, lots of chains to keep running and replace.  After doing maintenance and upgrades on this planter for the past 10 years I can't wait to set up our next planter just how I want it.  

Edit:  Forgot to add, we used to pull ours with a 7800 MFWD and now with a 8100 MFWD and both seemed to handle it fine but we're mostly flat to slightly rolling.