I have been on both plans over the past few years and I renewed on 'Simplicity' plan in November 2017.
It came down to a minor detail, 100 euro for private/hi-tech hospital admissions compared to 150 euro on Simply Connect.
Just to note, the 500 limit for day to day cover on Simply Connect plan also includes x-rays, ultrasound scans as well as gp, consultant visits etc.
MRI scans are dealt with seperately and are fully covered directly in certain hospitals/scan centres.
On a positive note, only the first 1 euro is not allowed.
One of my own parents is on this plan, which works well for them.
With Simplicity, re day to day cover, the first 100 euro is not allowed.
On a positive note, there is a day to day expenses allowance of 7650 per year per person.
It also fully covers a private room in a private hospital, which is worth a lot in real money terms.
Although a private room may not be a priority on your list.
Hope this helps with your decision.
Snowyb