Are you to be aware of the Sales Wolf really? Is this something to be scared of? Sean Hull writes a bit about this in a recent post but I think he got a few things wrong, although I also agree with a lot of stuff in there. Above all, I think Sean oversimplifies what Sales are up to.
Before I go on though, let me tell you that I have worked at Oracle, not only as part of the MySQL -> Sun -> Oracle transition but before that, actually my first job outside Telco and my first job for a US company was for Oracle. And I learnt so much stuff there, it was an incredible time. And not only was Oracle good at taking care of me and letting me go to classes and conferences and stuff, they actually helped me find those things and pointed me there. I went from a C programmer with some interest in databases to a decent support engineer and then to performance consultant and eventually a Pre-Sales Engineer, in a few hectic years. But I was younger then.
So, back to the real issue, is Sales just about getting the customer locked in and getting as much money as fast as possible from the unsuspecting management person, in the process bypassing the far smarter DBAs? Nope, that's not how I looked at my career as a Sales Engineer, I do not think I ever ended up selling something, together my my sales guys then, that I cannot stand up for today. Sales is so much more, just think about it, as there is competition out there.
Does your Oracle Sales Team really want to get unfriendly with the techies at the customer site? Yes, you often sell to someone in management, but just as often to a techie or to someone in management who is a techie. I there are very few Sales Guys out there who are both successful and is selling stuff the customer doesn't want or need.
Is the techie Ops and DBA guys really the experts? They know what you have alright, that is mostly correct, but they do not always know what the options are and what the advantages and disadvantages are. And again, this is natural: If you are a seasoned Oracle DBA, having taken all the classes in Oracle and knowing your TNSNAMES.ORA and INIT.ORA and other bits of Oracle inside and out, why would you want MySQL? MySQL is something you don't know? Why would you want something like that? I'm not saying that Oracle DBSs are bigots, quite the contrary, all I am saying is that we ALL have reasons beyond pure facts to react to things. It's not like a DBA or a sysadmin is necessarily more unbiased than someone in management, just because they know the existing technology better.
For me as a Sales Engineer, I think selling is about trust and about positioning. Can you trust me when I say Oracle might be a better choice for your database needs? Or that the answer might be MySQL? Or PostgreSQL? I'm really a curious person, and I really love to know what people are doing with technology, I am mostly not that interested in technology for the sake of technology itself. I'm not an Open Source taliban either, despite having worked at MYSQL for 6+ years (before that for close to 20 years at commercial closed source database companies, mostly). I like Open Source stuff mostly because it's a brilliant means of developing software. And yes, I have said no numerous times, and I have my sales guys with me (mostly)!
Look at a car salesguy. Does he want to sell you the most expensive car he has, then he is probably not a good salesguy in the long run, as you, as a customer, will eventually figure out that this car really didn't fit you that well, and next time around, you want to buy a car from someone else.
Having said all this, I agree with many other points in the post in question. Yes, make a list of things, if you can, but remember that the company trying to sell to you might have something you can benefit from, but which requires some effort or change on your side to change. Do not just just look at what you know and have experience in, but on what you can learn. If the technology isn't used in your industry, is that a good thing or a bad thing? If it's not used by your competitors, are there advantages to the technology that your can use to your advantage versus your competitors?