Pros: suction and speed control; hospital-grade
Depending on how long you want to pump, you might want to look into renting one of these for about $35/month, or buying one off of ebay for about $300-$400, if you can find one that is not stolen (most of them are even if the current owner doesn't realize it--call Medela with the serial number to see, if it's stolen they won't come after you, but you won't be able to get it serviced).
This pump is great for maintaining your milk supply. I used it until my daughter was 8 months old, and she never nursed, so it was all pumping. I only quit because my school plan period changed, and it was going to be too long between pumpings to keep going comfortably.
The suction and speed have variable controls, so depending on how tender you are, you can mix and match until you find a combination that works for you. Long and hard pulls, or short and gentle pulls. The more suction you can stand, the better--it will shorten your pumping time.
The pump is totally indestructible as far as I can tell. It has a strong body and comes with a plastic case for transport. You can also get a discreet bag specially made for the pump that also has a "thermos" like compartment for storing your milk in bottles and with a cold pack.
You can get car adapters for the pumps, although I found pumping in a moving car hard to do, both for discreetness (try holding a blanket over you while holding two pumps to your breast) and because the power seemed to decrease a lot, making the pumping take longer.
The pump itself is just the motor and the moving arm--you need to buy a "kit" which contains the cones to go on your breasts, the actual syringe-like mechanism that creates the suction, the collection bottles and lids, and the air tubes. Even if the pump comes with those attached, if the parts are not brand new and in sealed packages, for health's sake, buy a new kit (about $30). The kit will last forever. I used the same one the whole eight months. One note here: the reason you would want this pump is because the milk never goes through the pump, only through your pieces from the kit. Some cheaper pumps, besides not having as much power (battery or manual) actually run the milk through the mechanism, making it a one-user item. Do not buy such a pump secondhand. Some viruses are found in breast milk and may contaminate the pump itself, so when your milk runs through, it picks up the viruses.
You can pump one breast at a time or both at once, depending on your preference. The controls for that are on the plastic syringe-like suction device, not the pump.
The basic difference between the Lactina and the Lactina Select is that the Lactina Select has speed control, and the regular Lactina just has one speed. But really, the speed you will use will probably be so close to the one on the Lactina that you will never know the difference.
I like the Lactina models better than the Classic model mainly because they are smaller and less bulky or heavy. But they all do the same quality of job, and with Medela, you know it's a good job.