I cannot speak to comparisons with Seabourn or Regent. My experience with Oceania has not included air booking. I prefer to do that independently as well as pre post cruise stays. You can book transfers which I did once on board for the end of the cruise and regretted. Had to wait for bus to fill and think taxi would not have cost much more. I think that should be evaluated based on port, distance to airport, availability of taxi or Uber/Lyft and of course, ease of having luggage handling service. Specialty restaurant reservations allotment is based on cabin class and as noted previously depends on ship as far as number of restaurants. There is no extra charge (except as previously mentioned for the unique dining)and every cabin is guaranteed at least one reservation per restaurant which you can do before boarding when the booking window time opens. Depending on the length of the cruise, our ability to book more than our allotment once on board has been good but surprisingly, not as easy as on our recent Viking cruise, even though Viking only has 2 specialty restaurants. There are so many choices on Oceania that it is often abit hard deciding where to for lunch and even for dinner if you don’t have a specialty reservation. You can always get fresh grilled steak, salmon, shrimp, lamb chop at the buffet. I would rate the food on Oceania excellent (pre Covid travel) and overall better than Viking which was very good. There are more choices and more variety on Oceania. I was particularly disappointed in the breads, salads and pastries on Viking though the wafffles, soups and open face sandwiches at Mamsens were a delight. A consideration re alcohol is that you can buy a wine bottle package once on board. There will be a list of wines and you can mix whites and reds. We have travelled with another couple so each of us have usually purchased one 6 bottle pkg which means 12 bottles total. Depending on the length of the cruise and how much we feel like having, we have purchased maybe 2 additional bottles. Your bottle is labeled and your server can access it at any of the restaurants. The only time we had any difficulty was once when we decided we wanted wine at lunch at our table at the buffet when it took a very long time. You can bring on spirits or wine so we have had our own cocktails in our staterooms or weather permitting on the veranda pre dinner with an occasional purchased drink if we wanted to enjoy the delightful jazz pianist at the bar. Compare the prices of the packages and your drinking preferences. Having just returned from our first Viking cruise, while the generous refilling of your glass at lunch and dinner started off quite nice, for us, after a few days we found it abit too much and had to develop a modicum of control and moderate. In regards to the Olife options. We prefer the onboard credit which we apply to the basic gratuities and our wine purchases. Traveling with another couple, we have found booking shore excursions independently more rewarding and less costly. We have even done a small group tour connecting with others here on cruisecritic. I think it also may depend on the itinerary and what can be arranged. On our recent Viking cruise ( first post Covid), we only booked through Viking as we were not traveling with our friends and most of the independent tour operators had some cancellation penalties. With the uncertainty of potential Covid, we felt more comfortable staying with the cruise excursions even the ones with additional cost. Hope this a helpful.