My spectrapure litermeter died after 7 yrs of constant kalk use (assisted partially by me -- I tried opening the case after kalk leaked in; bad idea). I was very happy with this unit, and I would definitely by another. But $300+ was hard to sell to the wife.
Anyway, I have purchased a Tom Aqualifter pump for $10 and a $13 digital timer from local home center. The timer can do something like 200 on/off times per week. I will also be installing a small airline valve to further control flow. This set-up will take some adjusting of course, but having to add a little top-off water once a week or so to make things right is not a big deal. Also, to prevent major catastrophes I will limit the resevoir size to only approx 1 week of top/off. This way if the timer sticks in the on position there will not be problem.
Do some searching on RC, you will find people are having good luck with the aqualifter pump. Anyway this option is so cheap it just has to be explored. The litermeter has a maintenace kit that is something like $15 -- that almost covers the cost of my dosing set-up.
This is not a completely fair comparison. The litermeter is a great product and it has the capability to pump multiple solutions. Also, my pump would probably have lasted much longer had I performed the regular maintenance more regularly. Also, I had recently reconfigured the tubing (I moved my resevoir to the laundry room and ran the tubing through a wall). I did not leak test the new set-up with the result of kalk dripping inside the dosing pump. During the time that the litermeter was in operation, it never once failed to dose the correct amount of solution. If money is not a factor, and you want a set a forget solution this is the way to go.
My choice is based on a desire to find less expensive ways to enjoy my hobby, and to have a little fun tinkering with diy options.
Good luck.
Another option I looked at is the JBJ ATO level control system (should be able to get for around $80) used in conjunction with the aquamedic pump. I know little about this set-up. It seems a little complicated for my KISS, Keep it Simple Stupid), philosophy but I have a buddy with an aquarium maintenance business, and this is the system he intalls.
I currently have like 10 frags I will have to frag cuz they are really not frags anymore... I'm going to have to start giving them away or something.
