Persil Gel Tablets work really well, I quite like them and I'm fond of the scent.
The only bit of advice I would give you is to make sure you put the bag at the back of the drum when you load the machine. It makes sure they don't end up sitting on the door seal like a stray sock.
I have to say though, I have never had any issues with Persil tablets dissolving in our Hotpoint Aqualtis nor in a Miele, even on very short washes.
I prefer the Gel Tablets to the P&G tablets which you put in the drawer. I find the P&G tablets often disintegrate before you get them into the drawer and they can be quite messy to deal with if they do break as they end up all over the floor.
Unilever's approach while it does require a dosing device i.e. the net, avoids this problem as it allows the tablets to be a lot more solid.
The net basically ensures that the tablets disperse and also drags them around the drum - otherwise there's a risk they would simply sit on the door seal and not dissolve. (I have tried them without the net)
If you lose the net, you can always put them into a pocket of a pair of pants, or into a sock, a pillow case or a laundry bag. It works quite effectively
