The places which are recommended by the sifu's here are definitely legit. This is from experience as I bought from WhiteFlash before and experienced their excellent customer service. So reliability is there.

However, the process for fund transfer can be a bit cumbersome. MoneyMatch is easy to use but still need to go through one-time setup and verification. Also, I also got into a small delay at Customs due to product description but that was sorted quickly though it costed me around 2 days of delay. So, don't wait until last minute especially if the proposal has a fixed date like on vacation or something.

Then you have to find your own way to do the ring setting but the end result is a product of your preferences and is more unique than store-bought cookie cutter designs. I did mine at TJ and I do highly recommend them. Not only the setting was done beautifully, but I went back for a resize (not their fault, it was a surprise proposal and I had to improvise the finger measuring to avoid suspicion leading to slightly larger ring) and it was done quickly and without fuss.

You do save some dough but take on a bit of risk and effort doing all these things yourself. Still, I think it's worth it and is a small but interesting experience by itself.

However, if you still want a unique ring of your own preference and design but don't want to deal with the complexity of sourcing from multiple parties and confused by the many options, then I suggest you contact TheGemTribe. They can act as one-stop shop for your needs, but still offer a personalised concierge experience to customise whatever you like. Compared to those brick-and-mortar shops where the experience is very "mass market" and you just go into the shop and choose, they will sit down with you and talk about your preferences and parameters (both technical for the stone and of course your budget and the type of "feel" you want the ring to be).

This is also from experience when I contacted them for a customised piece of jewellery. Do note I get nothing from recommending them, just sharing experience.

Summary is I think both options are good depending on the effort you want to put in and convenience you prefer. I would only say you should avoid the traditional brick-and-mortar shops due to inconsistent quality and high prices. I went to so many surveying the prices and you do get less for the same price you would buying your own from WhiteFlash or sourcing through GemTribe.

Good luck!