I have been working on a large map with parcels and sales information.
To help the client I have copied and pasted an excel sheet onto the map, this results in a graphic that can be resized etc. and behaves normally. The spreadsheet has a background fill in excel for the top row.
When I export the map the background colour, blue, from the spreadsheet is not exported resulting in the white text getting lost. As a work around I created a rectangle from the drawing toolbar, made it blue and positioned it under the title bar of the spreadsheet graphic. This works out okay but isn't satisfactory.
If I recall correctly, in terms of fidelity to the original in our use, the most often having problems was an inserted spreadsheet, better but still with occasional problems (especially when resized a fair amount) was a copy and pasted one and the best was a pdf version added to a map pdf, either as a stamp or copy and paste. If you can't go the pdf route, you might see if resizing your sheet in Excel and then copying and pasting it with little or no resizing thereafter works better.
If you have it, Adobe Acrobat can help. I have the same issue with cells with different coloured fills. I usually print to a postscript file and then use Adobe Distiller to make a PDF for hardcopy printing.
I have found a more reliable (for me) method of including Excel data (at least it seems to avoid the hassles I have had using copy/paste) is to insert an Excel object and then adding datato this, rather than copy/paste. I also do separate paste column widths, paste formating and paste values. SO far the only problem I have come across is viewing in layout view (sometimes but not always!) where the text appears disjointed from the column layout (note that my mapping colleague does not have this particular problem even with the same mxd (go figure). I have not tried using colooured cell backgrounds so cannot comment on this particular issue.
One would think that Excel spreadsheets would be well known and the whole process be seamless and error free.
I typically use the insert an Excel object method. I typical insert a spreadsheet that already has all the text and formatting including colored backgrounds. The colors always come out right. The text comes out right only about 80% of the time. However, I have not tried adding an empty object and then adding the data to that.
Maybe that is the answer. Add empty Excel object. Open Excel with the data, copy and paste column by column from sheet with data to empty inserted object.