The whole scene is divided on the subject. On one hand you have 99% chances of ending up with a female from a feminised seed, but on the other hand you don't always get what you get from a regular seed.
Most of the growers point to narrowing gene pool with reverting sex as these seeds are produced by reverting a clone and pollinating another one from the same mother. In terms of vigour and health these will be the same most of the time, but phenotypes will carry alleles inherited only from the female line. Recessive genes might be pronounced strongly as in straight F2 if the line is polyhybrid.
Theoretically feminised seeds are also more prone to show intersex traits in flower (in veg they always do), however it's not statistical truth it's just broad possibility.
Keeping the mother from regular seed is a much better idea in long term though, cause these plants won't hermie as easy as feminised seed ones, but in short term you won't feel a difference. I sometimes hear that cloning is easier with regular line, but take it with a grain of salt cause I'm not a cloner.
Feminised seeds can save you some headaches though if you have space issues. Often outdoor growers prefer regular ones over feminised ones cause they have mire space and are looking for the strongest plants. I've had some fems of praised lines that were absolute runt of the bunch, but I couldn't say for sure if it was due to indoor environment that produced them or due to feminising itself.