Personally, I loved the LV. We stayed GV our first trip and switched to LV at the last minute on our second trip. Best thing I did! It was worth the money for us personally. I enjoyed getting up each morning and seeing the castle and lagoon in front of you. We could even hear some of the goings on at MK which was also fun! We stayed concierge in Hawaii so I can't be much help on a specific building. If you splurge and do concierge, nothing beats this. We made up the dollar difference just in breakfast and pop/water. If you spend all day at the parks, not worth the extra dollars. If you do like we do and split your time between the parks/pool, it was worth it for us. We'd grab breakfast on the way to the parks in the morning. We'd head back after lunch and grab water/pop and cookies/fruit, etc. and head to the pool. They would put out veggies, cheese/crackers very later afternoon and we'd grab a snack while changing to head back to the parks. Sometimes the offerings were enough for a light dinner! We'd do the parks in the evening and head back to grab desserts, etc. if we had time.
Hope this helps!