Anyone else noticed this?

I've heard of a few aggregators and was wondering if anyone here has experience with them. Maybe you can tell me what to look out for?
I plan to swap a fairly large amount between my own wallets but I really don't want to set up an exchange account with a balance or manually compare a bunch of services and read conflicting reviews which just adds to the confusion.
My top priorities are finding a good route and avoiding issues during a large transfer. It would also be helpful if the service had responsive customer support.
Has anyone used an aggregator for larger swaps? What should I check beforehand?