I have used an RCBS chargemaster 1500 Combo for 3 years now had one, fell out with it, sold it, bought another 'cos I missed it and recently sold that one..
Whilst it is a wonder of modern technology and has a lot going for it, I got fed up with overthrows, underthrows etc.. (this is a common criticism of the units) and ended up buying a beam scale and measuring twice on every load, removing or adding kernels of powder with tweezers on pretty much every throw.. It works perfectly with ball powders but struggles with repeatability with extruded powders... there are mickey mouse fixes etc such as using a mcdonalds straw to control the drop more but.. really.. a right PITA (and one has to obtain a US McDonalds straw as the UK ones are not big enough!!!)
I have now moved to a Target Master auto trickler with an RCBS 10/10 scale (although any good beam scale will work) the Target master is too slow to drop a complete rifle load (it was originally designed for pistol loads) but it is incredibly accurate and repeats loads TO THE INDIVIDUAL KERNEL..... EVERY TIME! it is also optical so doesn't suffer from local RF interferance and drifting like the RCBS (or any of the combined electronic scales) does, nor does it need leaving on to warm up etc.. etc..! plus it is battery powered and so portable should you want it to be.
I have bought a set of Lee powder dippers too and the process is simply dip, dump the load in the pan, press the button on the Target Master and the TM then takes the load up to the desired weight and as I say, accurate to the kernel every time.. this process also takes about half the time of the RCBS (which is the fastest combo unit out there!)
Just an alternative thought from a long time user... don't underestimate the power of old school! This system also doesn't require any mains power which, in some circumstances is a huge bonus plus there is very little to go wrong!
Cost wise... depending on scales you are looking at quite a bit less for the TM, scales & lee dippers, so a cost saving too.