Generally, the visual quality and functionality of a website has almost nothing to do with the likelihood that the company is legitimate or that it provides quality work. Certainly, most of the big, legitimate essay companies do have very nice websites; however, the problem is that so do most of the worst scam companies out there, because they invest a lot of money into very slick, professional-looking websites, precisely because that's exactly how they hope to represent themselves as legitimate. Conversely, some of the best small companies such as the sole-proprietorships run by independent writers who are among the best essay providers in this entire industry run comparatively simple, bare-bones websites. Most of them either were once or still are (simultaneously) some of the very best writers at some of the very best big essay companies, as I've pointed out many times.
I agree Writer4Life's point about the grammar reflected in the website copy, but I disagree with the other 4 elements of your analysis for these specific reasons:
1. The knowledge and friendliness of the support staff when you are making contact.
Nobody provides friendlier or more helpful-seeming "customer support" than the worst scam sites out there. Of course, all of that changes the instant they're in possession of your hard-earned money. Nobody needs to take my word for this: simply go through some of the complaints on this forum, complete with full transcripts of the "chats" with customer support teams before and after orders are placed. The rip-off sites invest most of their resources into their websites and their customer support, because they don't have to worry about actually providing the high-quality work promised. Conversely, those of us who actually provide the high-quality work promised don't really have the time to devote to endless "pre-sale" communications to convince anybody to use our services.
2. Is the support staff easy to contact (during business hours, which should be posted somewhere on the respective website)?
They can say whatever they want about their availability and support hours on their websites. Until you actually pay for an order, you really have no idea how much of that is true. Again, just go through some of the chat logs and email chains posted on this forum by customers who got ripped off by some of these scam operations to see what I'm talking about in this regard.
4. If you placed and paid for your order, how is the responsiveness of the support staff and your writer...
As explained above, once you've paid them, it's too late to use this information to avoid getting ripped off. The various chat logs posted in other threads on this forum clearly demonstrate a 180-degree turn from overly-friendly and personalized patient responses to every imaginable question to highly-impersonal and cold responses (and chats abruptly terminated by customer support after a few non-responsive or evasive answers) when customers have problems with their orders after paying for them.
If your project is more complex than originally thought, will the company let you know quickly and refund your money?*
Not necessarily. Many of their systems are automatic without any human being evaluating the relative difficulty of any orders placed through their systems. Typically, the first time that customers have any clue that there might be a problem with an order is either when they receive a totally-unusable piece of work for which customers have to request substantial revisions or a complete rewrite (see #s 1. 2, and 4 above) or when they receive nothing by the due date, contact the company to ask about the project, and then find out for the first time that no writer ever took the project and that it's just been sitting on the assignment board ever since the order was paid for. (Before I was prohibited from doing it here in 2010, I used to check some of the essay company boards as a courtesy to forum members who just wanted to know whether or not their orders had ever been taken by any writer at the companies for which I was writing.)
*[Quote shortened to fit the maximum word limit for quotes on this system.]