I've been using a Rena XP1 for about 4 months now and a Rena XP3 for about 3 weeks now, I highly recommend them as a less expensive alternative to the Eheim canisters, which are excellent but a bit expensive IMO.
The Rena is a very very simple canister filter, no bells and whistles but it's a solid filter, simple to use and prime, has a self shut off latch for when you need to disconnect it from your tank to clean it, and has virtually no bypass if any at all. The trays for media are basically boxes so you don't need to purchase Rena media if you really don't want to. I began purchasing my filter pads and water polishing media on my own and just cutting it to the correct size which is easy with the Rena.
As for long term reliability, I can't say for sure but they are a very simple design so there isn't a lot that can go wrong.