I was exactly where you are, about 2 years ago. I really wanted an electronic scale, but I knew I would eventually get a dispensing system. The reviews were mixed on both scales and systems.
I bit the bullet (so to speak) and bought the RCBS ChargeMaster Combo. It is a joy to use and I have had not one problem with it. If you buy the scale and unit separately, you are going to pay a premium. Currently at Cabelas you can buy the RCBS ChargeMaster Combo for $299.99 and get a $50 rebate from RCBS. So for just $50 more than your limit, you can have the entire system.
I can't say enough good things about the scale. It is always dead on, I use it to weigh by brass for sorting (try that on a beam scale) and it just works. There may be others out there just as good, but I only know how mine works.
The tuning of the dispenser makes it much better suited for rifle than lower weight charge handgun dispensing.