CLCL http://www.nakka.com/soft/clcl/index_eng.html
Light weight, portable and works well

Well, I distinguish between text edit and markup like these:

Example of text addition/Edit:
(a) Add text: I use this to fillup "wire transfer" information in pdf application form that I download from my bank's site. I open the pdf in an editor, add text in the appropriate places, save, print, sign and send.
(b) Edit text: In other instances, Pull up an old filled (such) form, open in an editor, edit earlier filled text like $$amount, account number, beneficiary details (as may be the case), save as a different pdf
(c) Markup: More general usage - like markup of comments / remarks / inputs in a pdf quotation / invoice sent by my staff. One can turn comment on / off. The basic text of pdf is not altered

Foxit editor does a pretty neat job of (a) and (b) - something I am used to.
Bluebeam probably treats everything as (c)