I asked the same question a while ago and the general consensus seemed to be native HTML.
Attached are some notes I made for myself and it is how I have inserted tables into the various articles I have uploaded. It is not as bad as it looks at first sight. With copy and paste the tags can be quickly inserted and it avoids the need to completely re-type the table in the editor.
Thanks for the info – seemed a little complicated for this non-html person. What i did was to save the table I had created in Word as a pdf and upload that – look OK.