For me, this would be an easy decision.
If I was going to replace the IMSB, I would unquestionably choose the LN Engineering bearing. My reason is simple. One of the most respected Porsche dealers in my area installs the LN bearing as a preventive measure against catastrophic engine failure. That says a lot to me.
BTW: In an earlier post today in this thread, I said I had not seen any hard data on bearing reliability. I looked at LN Engineering's write up today about the IMB kits and numbers are provided. See the 3rd paragraph from the bottom of the IMS 101 page:
IMS 101 | IMS Retrofit. The reported reliability is truly impressive