I too was in the same boat as you - VF's very polished Hex tune, or the latest craze surrounding these forums - bootmod3.
I honestly believe it'll be a never ending debate. However, choosing between the two was relatively easy for me. I have ultimately decided to go for bootmod3 because of its potential in tuning maps specifically to your mods, price, power curve, and features. I'll break down what I mean:
Potential in tuning: bootmod3 allows for custom maps. One of the most knowledgeable users on these forums, CaryTheLabelGuy, currently is customising his OTS (off the shelf) E30 stage 2 map to run a higher ethanol content. This is pretty crazy IMO! I personally will be eventually running port injection, in which case a custom tune for 100% E85 can be created for my car, then later down the line I may run a Pure Turbos stage 2 - in which case I can again get another map tailored to the mods that I have on my car. Bootmod3 has near endless limits to tuning capabilities.
Price: bootmod3 is literally
half the price of the VF Hex tune. The price quotes I received for the VF Hex didn't include the TCU upgrade for DCT cars either, this upgrade comes standard with bootmod3. I won't state prices, but I will say the money I'll have saved can be used on other worth while mods.
Power curve: check out the dynos that bootmod3 have provided on their thread. Your car will make power higher in the rev range, so it's a much more linear power band/feel than the VF Hex tunes power curve. I personally enjoy revving the car out.
Features: the ability to change maps as necessary is wicked. If I decide to run 93 fuel with about 4.3 gallons of E85 (making it about E30 if there's 10% ethanol in the 93) I can do that on their OTS E30 map. If I'm stuck at a petrol station where there's no E85, then I can quickly change over to a 93 octane fuel map to ensure smoothness and no harm to the engine. Being able to data log easily is also a plus.
All in all, if you're looking to customise and switch maps in your car, bootmod3 is definitely the way to go. The VF Hex tune is more of a set it and forget it type of flash. I thought I'd be the type of guy to prefer a "set it and forget it" tune, but doing research has opened my eyes in terms of what can be accomplished by this chassis and the S55.
As a small disclaimer, I have no affiliation with bootmod3 and am just an enthusiast. I'll be getting my bootmod3 done in the next week or two
Good luck!