Just a "few" words about gearing range and other comparison, in case you're unsure. Range from lowest to highest gear, solutions sorted by range:
Alfine 8: 307% range
10-36 cassette: 360% range
9-34 cassette: 378% range
Alfine 11: 409% range
SRAM DualDrive: 576% range in 3x9 standard setup (discontinued)

So you choose what range you need, and then pick a front chainring size (and/or Alfine rear cog) to adjust what your actual lowest/highest gears will be.

These cassette solutions (not the sunrace one) are likely stronger than the Alfines. The cassette hubs are low maintenance, no oil change needed. Cassette shifting is quite easy to adjust. Efficiency is also higher, less energy is wasted. And weight is likely less. On the other hand, with cassettes you'll need to replace parts more often (chains and cassettes). If you go on a long tour, it's best to do it with a new cassette, since these somewhat unusual casssettes will be hard to find in physical bike shops. Some like the e-thirteen can be quite expensive. You can't shift while standing still (except by lifting the wheel and turning the pedals). You can shift while pedaling, but you should reduce the force. Folding is best done with the chain on a medium/small cog (higher gear), a little impractical but no big deal. The derailer is vulnerable when riding, it will easily pick up grass, but is protected when the bike is folded.

With Alfine 11 you have a high initial cost, somewhat difficult shifting adjustment, higher weight, lower efficiency, and the occasional oil change (easy job). Though it's cheaper than the most expensive cassette solutions, and parts replacement will likely be very rare, apart from the chain (which is cheap). Range is good, you can shift gears while standing still, and it doesn't matter what gear you are in when folding. Shifting while pedaling is possible if you slow down the pedals a little and reduce force, or you can briefly stop pedaling. Alfine Di2 may not be possible. The chain tensioner is strong and holds your chain higher up from the ground (when using the minimum chain length, which I recommend also because it helps chain uptake when folding). If an Alfine breaks down during a long tour, the tour is likely over. It will be very hard to get it fixed. This is true for most hubs, but cassette hubs are stronger and less likely to break down (except the some like the sunrace 9t).

I mention the SRAM DualDrive because it gives you a huge gearing range in a cheap and fairly solid solution. You can use a very cheap 11-34 9-speed cassette. With the hub in 2nd gear it is in direct drive, and efficiency is the same as a regular cassette setup. However, it is discontinued by SRAM, so you'd have to search for a 2nd hand or old stock package. (Sturmey Archer still makes a very similar solution, but I can't recommend those as they likely use the same weak cassette hub body as the Sunrace one. I have had an SA cassette hub break in the same way as the sunrace, and it looked exactly the same.)
SRAM DualDrive

I think this is a fair comparison. Be aware, if you read reports about Alfine hubs being damaged: This depends on the torque you put into it, which depends on wheel size. Most bikes have large wheels and relatively small chainrings, which means high torque. The Birdy has small wheels, large chainring, and low torque. This should give any hub / chain / cog / chainring a longer life on a Birdy, than on a large wheel bike.

Spoke lengths: I learned wheel building from this book: https://www.wheelpro.co.uk/wheelbuilding/book.php
It recommends measuring the rim and hub first (don't trust data from the manufacturer). Then calculate the spoke lengths. So if you buy everything online you'll need to buy hub and rim first, then measure, then buy spokes. There are different ways to measure, which will give different results. So make sure you measure in the same way as is recommended by the spoke length calculator you use.

best regards