Never been to sunflower so can’t comment on it. My take on the other two:
H&C: more straight forward, cheaper. Entrance is on a busy street, so it can be a little daunting if you want to be discreet.
Garden: better looking/younger providers in my opinion, entrance can be a little weird depending on what time you go since once inside you have to walk by lots of legit offices to get to the spa. Lawyers, accountants, etc. nicer/newer facility. Neither have table showers. I got a 4 hand session for no extra $ once... I tipped them both but only paid 1 house fee. Never happened again, I guess it was a slow day
I’ve never been able to get more than a hj at either place although both are fine with roaming up top H&C never pressured me for more tip, garden has
ps. I called healing garden a couple of days ago and got no answer so I’m guessing they are still closed due to covid. Hopefully they reopen