There is a fair bit you can benefit and deduce from trying cheaper options.
There is something very nice about quality glass, it adds to the vaping experience. But glass is fragile, and can be expensive. So it's good to have a reference for what you're getting into.
I think you can deduce what will work best for you without experience, but it certainly helps.
I can only assume that the Mobius pieces offer about the best an experience gets with scientific glass. Crossing the border from scientific to heady, like Sovereignty, Seed of Life and Mothership. Adding colour accents is a personal flair, it really adds something to the appeal of using the object if you tune it right. But it's totally superficial, really you want the best performance, and that's what expensive American rigs offer.
The key difference is the time invested in the pieces creation, and the final appreciation between artist and user. It's art at the heady, colourful level, but quality scientific blowing is an art too. Art is priceless and value can only be attributed disproportionately between different people. American blowers use their products and that insight pays off in my experience. China has really upped their game over the last few years though.
Knowing what I know, knowing my own appreciation for vaping and the amount I do it, I'd have no qualms jumping straight into top tier glass. I have owned heaps of bongs over the years, and my favourites I've commissioned and helped design, but the best is a Seed of Life production piece, as the level of skill and functionality is basically perfect. I appreciate that, which is why I chose it.
My pick for Mobius would probably be the
Micro Matrix II, but you can't really go wrong with any of their line-up. Mainly it depends on how you intend to use it, as realistically that piece wouldn't work optimally with my desktop vape - so I'd have to choose a second pick.
There's a lot to consider, ergonomics, intended vape being used, future upgrades and compatibility, then there's the dynamic of the piece - water quantity, percolation, restriction and smoothness. Plus mouth piece angle, shape, joint position, size, angle. Then there's foot width and stability, are drop downs needed or will they be? Much to consider, but there's that many options there is certainly a near-perfect piece waiting to be scooped.
If I was looking at China glass, I'd only be looking at the flower of life/seed of life cut percs from clean clear glass, as they are the best designed and functioning pieces on DHgate. There's also TAG, thick ass glass, which are just glorified Chinese production pieces, but generally they are better quality than what gets flogged off on DHgate. There's so many styles, if you list your intended usage I can help throw some pointers out there, but it's a hard one to get right.
Edit: I forgot about the Mighty/Dynavap vape selection. Beyond that, consider how you want to hit the piece; standing up, sitting down, at a desk, on the move.
Things I'd consider with those vapes:
Mighty: tall, needs clearance between joint and mouthpiece. Versatile and high air flow - most anything should be alright, but you want to get the piece to balance well. It'd stand up just fine in the matrix micro ii, but the mighty will stick out in-front of your face.
Dynavap: small and versatile, but super high air flow restriction which is going to massively impact percolation. You just want a basic piece for this vape, but the matrix perc works reasonably with them. A piece with high airflow and minimal water is what you want.
On top of that, more water generally means less flavour, more percolation generally means the same thing. Straight fabs reduce internal air volume but increase surface area. Recyclers mostly require open airflow (vapour path) to function and help to minimise dry surface area. All of this changes the signature of the vapour. With a budget such that you have, it's probably worth considering a range of different sized pieces too.
edit 2: I feel like it's also worth pointing out, in about a month there will be big sales for 4/20
