I agree with excav8ter that the ICS update was worth it for me, but that's partly because I'm willing to overlook some of the problems in trade for some of the improvements. If it were me just getting a new a500, I would not update quite yet, at least until after Acer issues another update for ICS, which is likely already in the works. Here is why I would wait if getting a new tablet:
- Honeycomb is naturally more stable at this point, because it has had more time to settle and have bugs resolved.
- Many more apps have been soaked by many more users on Honeycomb, so you are less likely to see problems with apps on Honeycomb at this point in time.
- some popular apps that worked well with Honeycomb do not yet work at all on the a500 with ICS -- e.g., Sims Free play. It seems possible that the opposite may be true in some cases, but I have not seen evidence of this.
- some of the problems being seen by users of ICS on the a500 mimic hardware issues. This could be very confusing on a new tablet. It's always better to test new hardware on a more stable OS, so you can decide whether or not a problem is caused by hardware or software, and determine if you just need a replacement unit.
If in your position, I would defer the a500 system ICS update at this point. Honeycomb is an excellent and very stable OS for the a500, and is more likely to provide a better experience for new a500 users at this point in time. The differences in functionality between Honeycomb and ICS are just not that vast, and you will probably like your a500 better if you start with Honeycomb.
You can then save the ice cream sandwich treat for desert, after you know your hardware is sound, and after the ICS build for a500 has been made more stable by Acer.
You can skip/cancel the update to ICS while you are going through the initial setup. You will be asked immediately after connecting to your wifi network, where I recall that you can select cancel. I suggest you then go to Settings -> About Tablet -> System Update, and uncheck the box there. I would then check back in this forum or others periodically/patiently for announcements about a subsequent ICS update from Acer before initiating/accepting a system update.