initial_mode option defines the starting mode of the form view, one of view and edit (?). Default value is view (non-editable form).
embedded_view attribute has to be set separately when providing a view directly, no option available for that usage.
Form is not entirely loaded (some widgets may not appear) unless on_record_loaded is called (or do_show, which itself calls on_record_loaded).
“Empty” form => on_button_new (...), or manually call default_get + on_record_loaded
Form fields default to width: 100%, padding, !important margin, can be reached via .oe_form_field
Form will render buttons and a pager, offers options to locate both outside of form itself ($buttons and $pager), providing empty jquery objects ($()) seems to stop displaying both but not sure if there are deleterious side-effects.
Other options:
readonly fields probably don’t have a background, beware if need of overlay
No facilities for DOM events handling/delegations e.g. handling keyup/keydown/keypress from a form fields into the form’s user.