I'v used Tunze for many years - its excellent.
I found an old Tunze leaflet in a box the other day circa 1980 - on rereading the description of the 'system' range - its al currently accurate knowledge.
These products go on and on and are well thought through for maintenance and ease of access and with some imagination can be tweaked.
For example - with energy costs in mind - I've just added a sereis of computer fans to system bio modules to get evaporative cooling - works a treat - much cheaper and smaller than the deltec equivalent. the media is CAG to provide a more gentle use of this media
On skimmers - have started with tunze - moved to deltec and now back to tunze with an additional mod - because it just keeps on chugging along without the need for constant tweaking of air and water levels. With the mod it takes out dark skimmate too.
The streams with controller are unparalelled in versatility and power.
The autotop up devises are the biz.
The quick change mech filter is so easy - I actually change the mech media frequently and keep the orp up - no drips all over the floor - and very quick to do.
I use other brands to for different things - but Tunze has some great products.