Question 1

Does this work on all sega genesis models i have the model 1 with the volume switch

Accepted Answer

This controller will work on all models, however for certain titles, you will have to switch to the 3-button layout via the mode toggle function (by holding the minus/select button for 3 seconds).

Question 2

Will this controller be able to wirelessly connect to the 8bitdo wireless adapter usb for pc/switch?

Accepted Answer

I used mine on my PC and it must be connected with a USB mini. I don't have a Switch so I can't speak of that. The PC identifies it as a XBOX 360 controller. 
The buttons for PC are as follows:
A = 1   X = 3
B = 2   Y = 4
C = 6   Z = 5
DASH = 7
START = 8 
L & R = Z AXIS
HOME=MIDDLE BUTTON for XBOX 360
STAR=RAPID FIRE

Question 3

Any benefit to this version over the bluetooth version?

Accepted Answer

It has the advantage of allowing you to use other BT controllers (PS4, Switch Pro, Wii U, etc..).
Though the Bluetooth version is also $5 more for the M30 controller, and then you also have to buy a $20 receiver.

Here are the rated in out latencies for both (according to a recent test here https://www.retrorgb.com/krikzz-joyzz-vs-8bitdo-m30-2-4g-vs-8bitdo-m30-bluetooth-input-latency-lag-testing.html )
M30 2.4g = an unnoticeable 3.6ms
M30 Bluetooth = 21ms (which some people may notice, but most people won't)

Question 4

Can this be used with Raspberry Pi?

Accepted Answer

This version (2.4Ghz) will connect to Rasperry Pi, PC, or Switch if you use it as a wired controller with a USB cable. It will not work wirelessly with them. If you want this controller to work wireless with the Raspberry Pi you should buy the Bluetooth model which is $29.99. 
I have this version, it only works wirelessly with the included dongle which only plugs into a Genesis style port. 
The difference between 2.4Ghz and Bluetooth is products labeled as 2.4Ghz use proprietary connectors that will be bound to its wireless receiver(s) out of the box where Bluetooth is a standard many products use to connect so you can often choose different receivers that use Bluetooth as well.

ASIN	B07HB1XFQW
Batteries	1 Lithium Polymer batteries required. (included)
Best Sellers Rank	977 in PC & Video Games ( See Top 100 in PC & Video Games ) 1 in Sega Mega Drive Accessories
Country of origin	China
Customer reviews	4.4 4.4 out of 5 stars (1,379)
Delivery information	We cannot deliver certain products outside mainland UK ( Details ). We will only be able to confirm if this product can be delivered to your chosen address when you enter your delivery address at checkout.
Guaranteed software updates until	unknown
Item model number	6922621500834
Product Dimensions	14.4 x 2.6 x 6.3 cm; 90.72 g
Rated	Not PEGI rated
Release date	8 Mar. 2019

8Bitdo M30 2.4G Wireless Gamepad for the Original for Sega Mega Drive/Genesis - Black (Electronic Games)

Description

Specifications

Common Questions