Most people end up removing them out of necessity - hamsters tend to block up the tubes andpee in them and they end up a stinky mess. Dwarf hamsters would find it difficult using the tubes also. It works much better just as a standard cage without the external tubes and penthouse, and with a house at floor level, open underneath and sat on top of the substrate - that way they can have normal behaviours, bury hoards under their nest and tend to choose a corner of the cage as a toilet (syrians - dwarf hamsters may choose another area as a toilet). So it makes it easier to let them have normal behaviours, easier to keep the cage cleaning, by spot cleaning the pee area (or using a litter tray in the pee area is ideal) and causes them less stress because cleaning out the tubes upsets them if they've nested in them.
So they just don't work basically! It's better to have tubes and tunnels as floor toys - they are basically ground-dwelling creatures andonly really climb to get to something. Or short runs of tube attached to the bars, open at each end. Eg I had one "length"of tube attached to the roof of my cage leading between a house roof and a shelf or sputnik - so it was an access route rather than an enclosed system.
Also the plastic tubes can be too small for some syrians who could get stuck with full pouches.
If it's for either a syrian or a dwarf, then as you say, both would have pros and cons. The Hamster Heaven is a better height for a dwarf hamster. It would also be fine for a Syrian, but you may find it a bit cramped and feel the need to upgrade later.
The Alaska is a bit tall for a dwarf hamster and you'd probably end up having to spend more money on extra shelves etc to reduce fall risks. It's a better size for a Syrian, but again you may still feel the need to upgrade if you had a very active syrian.
They are difficult decisions money-wise etc. I started out with a cage the size of the Hamster Heaven and ended up upgrading to the 100cm Barney so ended up buying two cages! Three actually as my first cage was really much too small and unsuitable - and I wished I had gone straight for the 100cm one.
On the other hand it was good having a spare cage and I now have two hamsters and the older cage(Hamster Heaven equivalent) is used for our robo.
I think the Hamster Heaven may be the best option for a dwarf hamster. If you do get a Syrian in future, it may be fine, depending on the personality of the hamster - and if you wanted to upgrade, Hamster Heaven's sell well so you'd get some money back for it to put towards a bigger cage.
So I'd get the Hamster Heaven
But I would remove the tubes and penthouse and possibly the shelf with the holes in and just keep the solid shelf. That would also give you more useable floor space for a house, toys, wheel etc - and you could fit both a wheel and a flying saucer in. It would be best to add a house at floor level that is open underneath to encourage normal nesting behaviours and then you're unlikely to have to upset them by having to clean out the nest. They tend to keep the nest quite clean when it's on top of the substrate and it gets more air to it.
Just a cardboard tissue box is fine with the base cut out, or a child's shoe box eg. The Hamster Heaven is a more solidly built cage.