I prefer the Mandarin Oriental as I prefer to be on Hong Kong island for restaurants, shopping, etc. The Peninsula has great views back toward Hong Kong island but I find it too touristy and I don't care to stay in Kowloon. The in hotel restaurants are also better at the Mandarin, not to mention great places all around. Service is top notch IMO at both, but I would give the Mandarin the edge. I stayed for years there but must admit in the last 5 years have switched to the Four Seasons which is now my favorite. It has wonderful views, excellent service, good restaurants in the hotel and adjacent. Although I love the Mandarin I like the four seasons better today. I would skip the Pen, but that is me and due to location.