I just added a Fluval 406 with Fluval spray bar to my 75 gallon setup yesterday.
Seems very well made. I was told it is 15% more efficient and also quieter than the 405. Also improvements to the impeller housing durability. I think there was more, but seems to be escaping me at the moment.
I'm sure there are other great canisters out there, but the Fluval seems to be a great option.
I added SeaChem Purigen pouches to the upper tray during set up.
I was blown away at the dramatic improvement in clarity in the tank, having looked at it this morning after installing the filter the previous evening.
This thing is a silent beast!
If you can get a 405 for a steal go for it, but the 406 is only about $30 more on amazon right now. Seems like a no-brainer.