imgraphicscmyk

This didn't explain or answer anything that I addressed in my question... I have a VECTOR EPS file that opens up all jagged and places like a graphic in AD, instead of how it should like it does in AI.  None of the responses answer this or solve the problem any of us are having... or at least it's not very clear what the answer is.  The majority of the answers ignore the underlying problem or ignore the question altogether... we are not newbie designers.  I've been working with vector files in Adobe Illustrator for over 25 years!

The reason why that EPS can be opened faithfully in AI is because most of the guts of it is pure AI data in the private data section. AD cannot open that data.
The reason why the AI file can be opened is because it was saved as a PDF compatibility (Illy's default) and AD is only opening the PDF portion of the AI file. AD cannot open the AI portion nor open an AI file that is not saved with PDF compatibility.
I have one application other than AI that can open that EPS faithfully. An online converter may well be able to convert that eps to PDF. Maybe. It's worth a test.

You're most welcome, igCMYK...
I generally feel lucky that I have CS6 on Windows. So until Microsoft breaks something it'll work just fine for the times I need AI or ID. I have had need to rent for a month or two due to needing to return an ID file in CC format but have never needed to use a more modern version of AI for anything (same applies to Photoshop).
I use ID far more than AI. I create (relatively simple) original vector art and don't to often need deal with stock graphics. Once in a while a client will specify a particular stock EPS or two or I'll need to look around, offer up a few suggestions and go from there. I've not had many issues using my main vector editor but I have had an issue or two in the past. Then I'll use Acrobat or pdfToolbox to convert them to PDF and they then come in fine.
I suspect Serif will rectify some of these issues over time. AD is still a relatively young application. I do use it some to gain more fluency.
Mike

I cannot tell from the screen shots with the graphic in AI, but if there certain transparencies used on the gradients, certain blend modes, and if there are any mesh fills, AD will always rasterize upon import. That is because an eps file cannot contain such items. However, there may well be certain features written into the EPS that is AI data so AI can interpret properly. The copy/paste is then (depending on preferences) copying the data into a pdf format and that is something AD can understand as the structures are changed in the process to what a PDF can accept.
Sounds convoluted, doesn't it?
If that eps is from a free site, perhaps link to it so Serif can look at it and/or attach it here.
EPS, both in and out, of AD needs work. It's that simple. Adding the ability to open AI data would be a bonus.