I bought the LBL (Lady Leaks) version of these for medium/heavy flow while on sale. Arrived next day which I was impressed by. The knickers look good on (to say what you're using them for) and fit true to size. They have quite a well padded gusset (I had been put off from using period underwear before thinking they'd not be absorbent enough).
Used them on the first day on their own and really comfy and no leaks but used an extra pad overnight and when out and about, the following day.
I do suffer from very heavy periods and often need to use night pads during the day. The second day, I did leak while wearing these pants and a night pad, in about an hour and a half. So if you have really heavy periods, I wouldn't use these on their own until your flow gets a bit lighter.
I'd still use these pants though as extra protection/on lighter days and am thinking of getting some of the super period briefs for nights and heavier days as wearing these are so much more comfortable than using disposable pads (that don't always stay put, shrink up or chafe and leak when you move - why I thought i'd try these in the first place, as had gotten so fed up of having to wash PJ bottoms and knickers from the previous night regularly throughout my period and worried they'd be ruined from the staining). Overall, I am happy with this product and glad that at last, I can wear something that feels nice to wear, during my period.