Julia Dizzy - really I would not worry. The doses are designed to be exactly the same delivering exactly the same amount of estradiol. Potentially minor differences in pump mechanism (I've no idea) or the shape affecting the temperature of the gel inside - which could affect consistency but I am sure tests will have been carried out to ensure product quality is controlled. Most women don't notice any difference - the ones that do report on here (or apparently, mumsnet) but just don't worry about it. Those that have - some have said they need more, some have said less (in the past when similar issues have been reported).
If you are peri-menopausal then your own cycle will be coming into play and could affect how you feel due to changes in hormone levels. If you are post-menopausal, and feel you are noticing a slight difference for whatever reason - then the beauty of the gel is that you can tweak your dose to suit - either increase or decrease.
But above all - don't go looking for problems and you will most likely be fine
Hurdity x
