"I have my 405 running in a 75-gallon freshwater tank.
Setup is easy, priming takes a few good pumps - you might be tempted to keep pumping when you don't hear water rushing into the canister, but just relax: water IS flowing, just wait for the air bubbles to cease.
The hoses do come straight out of the top of the canister. Some people have had trouble with this, but the hoses provided are long enough that you don't have to position the canister at the back of your cabinet... just run some extra hose. There is plenty of hose supplied, just cut it longer.
Maintenance: takes longer than simpler, weaker filters. Just some running water, cheap wire brushes, once a month. Your investment needs to be taken care of properly, but it's really not so bad. 15-20 minutes for me.
The carbon that comes with the product doesn't fit well into the media baskets, so I just got more mesh bags (that's my only complaint).
ALWAYS have an extra O-ring on hand. If you check them for dryness every time you maintenance, you should be fine. Put your canister in a bucket in case a leak occurs. If your O-ring literally "blew", you have to just blame bad luck, not the product.
If the canister is making noise, you should check for an air leak... especially if you have had trouble priming. The Fluval should be VERY quiet!
Finally, you should get a canister filter package-rated above the size of tank - shoot for a turnover (gallons per hour) of at LEAST 4X the volume of your tank (10 gallon tank = 40 gph, 50 gallon tank = 200 gph, 100 gallon tank = 400 gph) This is not excessive; fish appreciate water movement. The ratings on the boxes are really just bad marketing practices :)
Best of luck with your aquaria!!
~M"