I got it last Wednesday, and it's all I've been doing for the past week, explaining why I haven't updated. And through completing it with the help of Marilland's walkthrough (and here are some things he missed, so I'll be contacting him about it), I've found it to be addictive. I haven't even touched Ranger and Diddy Kong Racing DS (supposedly a remake of the Nintendo 64 game, and I've heard that Banjo and Conker have been dropped since Rare moved over to Microsoft) yet.
Then again, that happens with every game I get; I get deliberately stuck. That, and I haven't had any WiFi battles yet, although I have 8 numbers registered at time of writing. And all the while, I have posted that I'm training, yet a lot of what I'm doing is working out the cogs (caves, items, buildings, etc.). Simply put, I'm a slow mover, and I have to focus just to get my team trained, which is difficult considering the landscape and lack of competent trainers. I miss Match Call, which let you come across trainers in Sapphire who obviously have improved; instead you have a VS Seeker, which you got in Fire Red to rematch everyone (some not changing level at all, but others making some headway).
What I like in particular are the changes in battle rules, particularly the contact attributes. It now seems fair that Fire Punch, for example, is a physical move instead of a special one by type default (although it still made you susceptible to Carvanha's Rough Skin). Now it seems a little odd that you have a stat for use of certain move elements, which undermines type match-ups, which are probably one of the most crucial aspects of battle. Also to be mentioned are Quick balls; they make it easy to capture Pokémon and eliminate much of the fainting mistakes.
What I do not like, however, is the registration of a Pokémon as seen being enough to get a National Pokédex. Rather, the National Pokédex should have been given if you had captured a minimum amount, as in Fire Red. In fact, I strongly believe it takes much of the objective out of training. Then again, you get a colour upgrade for your Trainer's Card if you do capture the whole bunch of 493.
All the same, it's an excellent instalment — it's just that I have yet to get some people who will actually battle and not be so arrogant about it. I'll have my credentials posted later on.