I recently took several LX flights that were operated by Helvetic, Air Baltic and Edelweiss. In summary:
Air Baltic
Crew is from Air Baltic. On several flights they were rather unfriendly and do not seem to understand pax status structure within LH Group. Service is done "by the book" without understanding the concept of Swiss hospitality. Emailed to HON service about the shortcomings only to be told that crew is in training.
Helvetic and Edelweiss
Crew was very similar to what one can expect on a SWISS operated flight. Some were great, some were... just there and delivered the service.
Overall, Air Baltic decision seems to have filled the gap of LX insufficient aircraft count, but it hurts on the service level.