Tank Heaters

Hi, Have had my heaters in my tank now for about two years and have always changed after this length of time. We are using Eheim classic canister filters and are considering some Hydor in line heaters. Does anyone have any experience of these good or bad as it would be nice to get the heaters out of the tank and out of sight.
One concern I have is that there is no back up, whereas with 2 standard heaters at least if one fails the other can take over for a short period. The tank is alarmed against high and low temperature so from that point it covered. The idea of the heater outside sounds great, but just wanted to get some thoughts before I spend £50 on something that may or may not work well. The tank is 360 litre with a large shoal of Congo Tetra, and 4 Clown loaches and a couple of Bristlnose plecs.  Thanks

Hi Skull took your advice, probably on of the neatest items of equipment I have bought. Saving up now for another for my other tank now. Thanks.