You don't give enough specs of your Eco-Worthy $1359 "deal" to offer comparisons and you don't mention if that is USD or CDN dollars.
I recently bought 2 - 16S DIY boxes and 16 - 314 AH EVE cells from
Luyuan, which in all my looking, was the best bang for my buck AND was a trusted supplier, as I had dealt with them before, as have many on this forum. They are perfectly functional boxes, good quality EVE cell products that I have been very happy with for my 2 - 8S batteries. I am still waiting for my latest shipment, which hopefully will arrive in the next 1-2 weeks.
The Luyuan DIY kits were still several hundred dollars less than pre-built, but pre-built were still not a bad price from a known quality and seller. The main thing is finding a trusted seller of quality cells, because with pre-built batteries, you have no idea what cells are actually being used vs. marketed, nor their history, storage, matching, age, etc.. With Luyuan, they are busy enough that their cells are all pretty fresh and matched and no negative users that I've found.
There were one or 2 minimally lower priced suppliers "sometimes" but their prices varied too much every few days and I did not trust their battery cell quality as much as there were just not enough forum impressions. Brands like Hakadi, Yixiang (had more users but a few negative experiences), Apexium, Docan, Gobelpower, Eel and others were just more expensive for dubious benefits and quite a few mixed or bad reviews.
DIY is lower cost but a few tools are required. For pre-built, Luyuan to me is a quality supplier, with decent functional quality boxes and no BS. I have watched many reviewers of batteries from the likes of Gobelpower, Yixiang, Eel, Seplos, Basen-Green, Qishou, Apexium and others and they all have their pros and cons and are all more or much more expensive than Luyuan but the others maybe have one or two bells and whistles, which in my experience are not worth, to me, the extra cost for function vs fashion.
Sadly other options already in Canada are 2-4x or more in price.
By the way, you can not go 100% off the Seller Alibaba web page for pricing, or at least not for DPP shipping. You must always contact the seller directly via an Alibaba account or WhatsApp contact info from their website for exact location DPP shipping costs.