Which line is better, i.e., cabins, entertainment, service, dining and spa? Also, which offers the better shore excursion packages. Is cost similar? Are there better ships per line as well?

Both these lines specialize in Alaska, but my vote would be for Holland-America. Their cabins are larger, their ships are smaller allowing them to get closer to the glaciers, their food is slightly better in my opinion, and if you're going to Denali, Hal offers a tour that goes further into the park to see more animals. HAL has a more relaxes, less hectic atmosphere as well. Some might give Princess higher marks in entertainment, but I think this is debatable, as are most of my opinions. But since you asked, I would advise you to go Holland-America.

Another vote for HAL

Yet another vote for HAL. We've done two Alaska cruises, both the HAL and both were great experiences. We've not done Alaska on Princess, but did the Panama Canal and a South Pacific cruise with them. Also very good, but I'd rate HAL a bit better for food, service and atmosphere.

Have only done Princess to Alaska, and had a completely favorable experience. We did our own shore excursions (the folks at CriuseCritic) are fabulous. Loved the Crooners Bar for fun, liked all our meals. Anytime dining worked for us. Either way, you will love Alaska. Glacier Bay was important for us. Also did float plane to bear watching, helicopter landing on a glacier, the train ride. Do your homework and have a great time.

First off, before you pick the cruise line, you have to pick your itenary. What ports and glacier/fjord you want to visit? What time of the year? North bound? South bound? round trip? Vancouver or Seattle?

Second set of questions: What is your comfort level with fellow passengers? Do you like the bigger ships or the medium size ship or the really small ones? What type of on board entertainment do you like? What is your travel style?

Once you find your answers to the above questions, you can then choose what cruise line or ships better. Is the itenary more important than the ship?

The answers to your quetsions are:

cabins - the sizes are very similar but I like the pricess lay out better on most of their ships. More clsoet space.

entertainment - the larger the ship, the more variety of entertainment available. The Princess entertianment line-up gears towards the 40-60 whereas the HAL gears more towards the 55+ (That's my personal opinion).

service - both are about the same. With foreign workers, they all work for tips and they both seems to have decent staff retention.

dining - HAL is bit more traditional but I liked the Princess anytime dining. Dining room food quality are about the same but I will give a very slight edge to HAL for the buffet. Sabatini (Princess) is good value in my mind.

spa - sorry, both are pricy and my DW avoided them. You can get much better value and quality from your local spas.

shore excursion packages - they are almost identical. They use the same tour companies and stop at almost the smae places. The price are almost the same. (The same goes for all the cruise lines. Took similar excusrions from Celebrity and Princess and they use the same tour company)

Is cruise cost similar? - it all depends on the time of year and the type of voyage (one way, return etc.) To properly compare the price, pick cruises that are almost identical in time of year and ports, otherwise, you will be comapting apples to oranges.

If you have not cruised in about 5 years or so, a lot have changed through the years. And I forget who have said it before but I will repeat it here, cruising is NOT the same as an all inclusive resort. Be prepared to pay the extras (or call it nickle and diming if you want)