Well I did have a booking at the Regent before Easter followed by the IC however my partner died so didn’t get my first stay there . I have spent many hundreds of nights at the IC and it is my favorite of all ICs that I have been to .
However if you have status with IC then you should get an upgrade to a deluxe room if not then shower is in the bath which I hate .
If you plan on sightseeing then the Regent is in a better location.
The IC is convenient for the KaDeWe and western center.
Food and drinks in IC are less expensive
If you are up for paying for lounge access at the I C then it is like being in a boutique hotel apart from the rest , however book it with them by email in advance
I hope this helps