Is this nitro or E-Buggy? If nitro I would go for the HV so you can run a 2S lipo rx pack and not have to worry about cooking the servo. If its E-Buggy then you can probably set the voltage from the ESC so thats not such a drama. If its E-Buggy then choose whatever suits your budget, specs etc.

I have an MT4S and find the tx to be a decent size, not particularly small like a Futaba 3PV for example. I've seen the MT44 and MTS and they don't look that small to me, they look similar to my MT4S. Can you check out someones from the track to see how it feels in your hand?

With your Radio Suggestion, MT44, given my son races a MT-S (similar radio), and I have my trusty 4PX, we have had a lot of success with the Protek Servos, such as the 160T, and the 170SBL, 170TBL. Also the MKS HBL550 has been super awesome, for the price and the ability to run anywhere from 6-8.4V , its a very versatile choice. Just make sure to take into account your ESC, and if it has adjustable BEC or not, this should further help determine what you will be able to power Servo wise.

Either way, there are many choices for a good deal, Power HD is on the come up, and from what I have used their servos are a steal. Just shy away from anything that may say hi torque or speed, yet is running Plastic or composite gears!

The MT-44 is an excellent choice, as is the MT-4S if you see one pop up and want the same latency/response at lower cost.
The menus are intuitive and you don't really need to mess around in there much beyond initial setup, you'll be fine.

I'd much sooner put money into the best servos you can afford than blowing it on a radio with a bunch of surplus menus and features (most of which offer little practical benefit for most people in 1/8 offroad, from what I've seen) - the only thing that really matters in terms of the RX/TX is the latency and response. To get the best response on the MT44 you'll want to manually set your steering from "NOR" to SHR or SSR mode (and then re-bind to the RX, with RX/TX antennas held in close proximity). Any good digital servo is compatible with SHR, whereas SSR (A Sanwa-specific mode) needs a Sanwa SRG or PGS servo. The refresh rate itself (thus servo response, for the most part) is the same on this particular RX whether you use SHR or SSR (384Hz), SSR I believe offers a marginal improvement in latency due to a narrower pulse width. Many people can tell the difference between regular and SHR mode, but between SHR and SSR (correctly set and bound) most would likely not notice.

My recommendation (if you want to exploit the best response the MT44 offers) is a Sanwa SRG-BX or PGS-XB. If your ESC has a 7.4V BEC and you prefer faster servos the PGS-XR would also work.
I'd alternatively also consider just using the SHR mode and using Futaba's new HPS CB700 servo. The Futaba S9373 mentioned earlier is a fine choice too, but the brushless CB700 replaces it and can be had for similar pricing. The reason I'd stick to Sanwa or Futaba servos is both companies pay attention to current draw, which means you don't have to worry about your ESC's BEC (the power supply for the servo) being stressed, and avoid problems where the servo causes BEC voltage droop under load (or worse, brown-outs with cheaper brands like Savox). I'm sure there are other good brands out there, but I've personally seen both Sanwa and Futaba's high end servos measured for current draw at stall (usually max out at 2-2.5A, occasionally 3-3.2A but rarely more).

If you do decide to just run SHR mode and non-Sanwa servo, it's worth noting that the much cheaper MT-S radio offers the same response in its SHR mode (only!) as the more expensive radios (MT44, MT4S, M12S), and still has a nice display and most of the useful features. If you do have a budget limit and can't cover both the MT44 + aforementioned servos, I think smart money would be on the MT-S / CB700 combo run in SHR. The MT-S feels much the same in hand as the 4S and 44 too, so no worries there.

You'll want to set your ESC's BEC to 7.4V if that's an option (which ESC are you running?), and the response mode for throttle can be set to SHR.

Hopefully not too confusing, just figured if you're splurging on an MT44 you may as well know how to get the most out of it.

that does the job for 1/8 off road. it does NOT need to break the budget. buggy and truggy, so i'm in the market for four. YaY.