For a new startup I would look at the uncured. It is usually a lot cheaper and, like you theorized, work for cycling your tank. If you want to save a little more you can get dry rock and use some along with the uncured LR and it will become "live" in a short amount of time. Some people use dry rock as a base with the LR placed on top but you can use the dry anywhere you wish. The "cured" stuff has just been sitting in the tubs longer and most of the dead matter has come off. It is best to use the cured in an established tank that you want to add rock to but not have any ammonia/nitrite/nitrate spikes due to potential harm to livestock.
I am a fan of nice live rock (been called a LR snob before but hey, I like the way nice rocks look) and have always used uncured LR to cycle my new tanks. Most Pacific island live rock is now "pre-cured" before shipping. Basically, it is set on racks and a saltwater mist is sprayed over it for a few days to a week. Stuff like large dead sponges are removed. A decent amount of the life on it can survive but most pests i.e. crabs, snails, and mantis shrimp leave the rock before packaging. Any leftover pests usually die during transit. You will still have some more die off amd a lot of it depends on how long it sat in the box. Most rock, currently including all Fiji islands (even Pukani, Totoka, etc) are loaded on a boat once boxed and shipped. The rock is in the box for up to a couple weeks. Some "premium" types like Manado, Vanuatu, etc. are flown from island to LAX then shipped to fish store from supplier. They often have little die off compared to the boated rock. Some people opt to go with almost all dry rock and just add a little live rock to seed the tank. The thought being, besides saving money, is the lack of potential pests. Only problem I have found with that logic is that some pests may be easily introduced as you add livestock so the point is moot. A lot of eggs and critters can survive the coral dipping process. To me the benefits are cost and ease of aquascaping if you wish to drill rock and use rods or epoxies to hold the rock together.
As far as "what is good live rock" there are just a few simple characteristics. Get shapes that you like including ones to make shelves, caves, etc. The more nooks, crannies, and holes the better. Skip any pieces that are really dense and/or rounded that look like bowling balls. Dont pick pieces just because they have good color or what you think is a free coral growing on it. Most of the coralline and other stuff is dead or dying. An ugly colored rock will color up eventually. You just need to focus on getting the best shapes you can to try and make the aquascape you wish. Dont be nervous about using the uncured and/or dry rock at this stage or getting some cured rock that you really like. Most importantly, just have fun with it and dont stress. I enjoyed the aquascaping process immensely however I don't know if the beer I drank helped or not.
