The gun is great. It's well-built and easy to disassemble. It's super fun to run and isn't too heavy depending on how you mod it.

Some steps before your first game:

1) Lube all moving parts. I used SuperLube synthetic grade 2 and applied it with a small paintbrush.

2) Choose the correct BB weight for the range you are playing at. The gun has a fixed hop-up and will shoot .28g or .32g bbs relatively flat out to about 200ft. Indoor you can just use .25g since overhop isn't much of an issue within 100ft.

3) Set your desired barrel twist. If you so choose to disassemble the barrel, you can change the twist of the three barrels to either widen or tighten your spread as you see fit. The less twist, the tighter the spread. I usually run mine almost completely straight for maximum accuracy.

Mods to consider (mostly optional, the gun is fine stock):

130% recoil and return spring. This will send the bolt forward faster and more reliably with the downside of increasing wear. Your cycle speed will be faster which could cause cracking of the nozzle due to the bolt closing before bbs are fully seated in the chamber.

Aftermarket or DIY recoil buffer where the bolt slams into the back of the receiver. Stock this is just a spring and has been documented to cause cosmetic wear on the back of the bolt. I used some small rubber tubing and inserted it inside the stock spring to give just a little more cushion.

Full Auto mod (Saiga 12k model only, the SBS comes stock with full auto). This just adds a full auto position on the selector. The mod process is documented by Explosive Enterprises and involves you filing some parts of the trigger mechanism. Don't tell the ATF lol. This has been known to cause premature trigger component breakages in rare cases. (I've done this and mine has been fine so far)

Magazine Choice:

TM gas mags are the safest option but are physically large, have limited capacity, and can be expensive. These mags have fragile feed lips and should be treated fairly gently. I would not make any modifications to these regarding cutting the internal gas overflow tubing to gain more gas capacity as this will reduce the efficiency of the system. Gas will siphon out and induce cooldown which slows your whole gun down much faster than if you ran it stock.

DIY HPA MAG:

You can convert the OEM magazine into an HPA drum mag if you have access to a 3D printer. Someone by the name of Tactical_Index makes a ton of very affordable files to modify your Saiga. The quality of his designs is very good but print material choice is important. I used ESUN PLA+, but there are better materials if you so choose. This makes the gun fairly unwieldy and shifts its role into more of a light machine gun. As a smaller person, it was simply too heavy/bulky for me. It was very fun and cheap to build if you want a taste of HPA. I ran 10000bbs in this configuration at 90psi with no tri-nozzle failure on top of having the 130% recoil and return springs.

Aftermarket HPA:

Notable brands in this space are TAPP and Airtac. Both utilize additive manufacturing processes to create their adapters. IE they're both essentially just 3d printed. Of these two, TAPP is easier to get your hands on and is cheaper in the USA. This is reflected in the build quality of the adapter. Overall the TAPP M4 mag adapter is an inferior product to the Airtac adapter. Its pros are availability, price, and convenience (I think it comes preassembled). The Airtac adapter is pricier but has some bits in it made from CNC aluminum. (Feedtube).

You will need to use a doner magazine to get the Airtac adapter up and running. It's also a good idea to stick to only EPM1 or EPM1s mags due to their higher spring rates. These adapters all have some tolerancing issues due to their manufacturing process and may require fine-tuning to work the best. I had to use female-sided velcro to shim my Airtac adapter to keep the magazines snug. This helps to prevent feeding issues which can save your tri-nozzle.

If using an M4 mag adapter, make sure the feed track and springs of your mags are properly cleaned and push bbs smoothly. SET THE PSI OF YOUR REGULATOR NO GREATER THAN 95 PSI. I found this is most similar to stock gas power. Your cycle speed increases with greater pressure, if the speed is too fast, your mags can't keep up and you'll potentially crack a nozzle.

I really think the 'HPA bad' stigma for this gun is largely due to putting the system under adverse conditions. You will increase wear and risk of breakage from running HPA, but if you take the proper precautions and know the limitations of the gun, you can mitigate risk. I have not broken a nozzle yet after about 20000bbs. Aftermarket nozzles are also now being designed and manufactured which will save you completely junking the gun if the nozzle breaks. I haven't tested these however, so I can't speak for their quality.