Fundamentally, I consider the idea of having to fork out your own money to do the necessary due diligence so that you can have a chance to make an informed/unconditional offer, to be stupid beyond words. I'd rather take my time to negotiate, get a price that I can live with, make a conditional offer, and then do my DD. I've known of people who have lost thousands on inspection reports, valuation reports, and the like just from bidding and losing at auctions. Not my cup of tea.
Now of course there are definitely bargains to be had at auctions, so don't necessarily dismiss them out of hand. But it's not my thing.