Several issues and/or opinions (okay drama too) has been posted on this forum recently regarding Ipsos. So I guess it depends on which issue you may be referring to.
There seems to be a lag in editing and payment from time to time, but typically I am paid in 1 to 2 weeks. I've never been paid past the 3 week window they guarantee. With the holidays coming up the current pay schedule of once a week, will be twice weekly. Hopefully they will have sufficient editing staff to handle.
Some shoppers are not happy with the work to pay ratio for some or all shops. They are not the highest payers by any means, but guess it depends on what is acceptable or not to the individual, where you live, and what you are attempting to achieve via mystery shopping. Often it may mean waiting until a shop is bonus'd to self assign or asking for more than that when necessary.
The process for bonus requests and travel expenses has changed. A bit more analytical than on the have to get it done on the fly. I do not shoot low in my bonus or travel requests and always ensure there is a profit built in. I have not had a request declined since the new process has been in place.
I'm sure there are other issues other posters will chime in about.