Help me choose!

Hello friends,
I am searching for a good shutter tester. I have found many good options and I have narrowed it down to two. Please help me choose, I am very new to this and it is very hard to find specifications on these two models:
The first unit is a Kyoritsu EF-511N: price is $1500, I dont know the specs but the unit is a used unit from Kyoritsu and it comes with all the attachments and also will be adjusted and maintenanced prior to shipping.
Second choice is a Kyoritsu EF-8301: price is $2000, I dont know the specs on this either, this unit only comes with a 35mm attachment and the last time it was adjusted was 6 years ago but according to the seller "it is precise", but this unit is more modern also.

Please help me choose. I included photo of each unit.

Many Thanks, Henry

I'm surprised that you are looking at shutter testers that are so expensive - you must be looking for extremely precise measurements. Sorry - I don't have any experience with either of these. I have one of the little ones from Calumet that only cost something like $100 and it has served me extremely well through the years. I don't believe they make them any more, but perhaps they might come up on the auction site from time to time.