MP150 or MP200

The MP-150 and the MP-200 share cartridge types.
Not saying it’s the way to go unless you are trying to keep spending increments low, but I bought the 150 for about $347 and a year or so later, picked up the JN-P200 (MP-200 replacement stylus) for $169 from a eBay Nagaoka dealer in Japan.
The MP-200 cartridge can be had for around $450-$500... so yes I paid a little more, but not much.
Note that the MP-500 Stylus is not compatible with the MP-150 or 200 cartridge, so the incremental upgrading stops with the 200. The JN-P200 stylus is not compatible with the MP-110 cartidge either.
I liked the MP-150 a lot and did notice an obvious improvement with JN-P200 stylus on my (budget system in this neighborhood) system. Better detail in percussion, brushes, stringed instrument fingerings, etc. Bass tightened up slightly... a little less "boom" and better detail as well.
My (phono) system: Technics SL-1610, Pro-ject Tube Box S2 phono stage, Emotiva pre-amp, Morrow interconnects and ZuAudio Libtec speaker cables feeding Magnepan 1.6 speakers.
I enjoyed making and hearing improvements and now I have a 1 year old, spare MP-150 stylus in case I do the unthinkable and damage the somewhat more delicate boron cantelever on the JN-P200 stylus.

I would go with the MP-200 with the boron cantilever and elliptical stylus over the MP-150.   I purchased one a couple months ago to replace a Grado that came with my new VPI Cliffwood TT and LOVED it. Great balance across the spectrum. Then I came upon some unexpected cash that enabled me to upgrade to the MP-500 which has upgraded electronics and line contact stylus. If you are definitely interested in the MP-200, contact me and I will give you a really good deal.

Chakster, whether the Sony or the Nagaoka cartridge would be better would depend on the tonearm. For medium to high mass arms the Nagaoka would be the better choice. If you had a really light arm then perhaps the Sony might be better. The Nagaoka has many fine reviews. I have not seen one on the Sony.

Sony XL-50 on its dedicated headshell is much better cartridge than Nagaoka MP-200.
It is one of those cartridges that can be found today for reasonable price.
If you have not seen a review for Sony I am not surprised, the XL-50 and XL-70 were the best MM cartridges Sony Sound Tec Corp. ever made (in the 80’s). At that time SONY was pretty serious about analog (cartridges, turntables, tonearms).

SONY established Sony Sound Tec Corporation to produce phono cartridges. Not every equipment manufacturer can make a phono cartridge, but the Sony Sound Tec Corp. combining all the passion and knowledge has released some very interesting models in the early 80’s. The XL-50 is one of two finest Moving Magnet cartridges from SONY. Very special features are as follows: The Joint-less delta-type core; Boron Pipe cantilever and nude Super Elliptical Diamond; A screw holds the stylus holder firmly in place; Distortion caused by flex is virtually eliminated; Cup-shaped damper and tension wire! This lightweight and high compliance cartridge is designed for low mass tonearms. Loading recommended by the manufacturer is from 47k Ohm to 100k Ohm. Cartridge output is 2.0 mV. Frequency response is pretty wide: 10Hz - 50000Hz! The price for XL-50 was ¥25000 in 1981. Boron Pipe cantilever is nothing but a grown crystal of Pure Boron into a pipe configuration (wow). A tip mounting hole made using a laser beam. This technology is no longer available, instead of ultra lightweight PIPE configuration you can get only heavier Boron ROD configuration from cantilever manufacturers nowadays. Boron PIPE is associated ONLY with vintage High-End cartridges (MM or MC). I have two samples of SONY XL-50 and this is an excellent MM cartridge with exotic cantilever!

Nagaoka branded Jeweltone in Japan and all new models are just a versions of the very old design from the 70’s. Jeweltone MP-50 is Nagaoka MP-500. An old Jeweltone/Nagaoka MP-20 is new Nagaoka MP-200. Nothing new here @mijostyn

The mass of my Project 1 expression 2 carbon fiber tonearm is around 8.6 grams which I understand is on the medium side . The specs on the compliance of the Nagaoka MP110 puts it a little on the low side for a moving magnet cartridge . After over 50 hours of breakin sometimes I was having a little dryness with upfront sound on some recordings in the uppermidrange . Put some blutack on the headshell to see if the uppermidrange forwardness was caused by compliance problems between cartridge and tonearm .
The forwardness was subdued greatly up to the point where its not a problem anymore . 
I like the MP110 very much . It's a very coherent and controlled sound that hardly ever irritates . Its bass is not the most powerful or tight but is in line with the sound spectrum of the cartridge . It doesn't jump out at you but its there when you want to hear whats going on down there .
Come to think of it this would describe the sound of the cartridge as a whole .
Now what is it that I don't like about its sonics on my turntable that has prompt me to upgrade ?
Its lacking of low level detail . It seems that it is so smooth that in its intent of always sounding smooth it took away a bit to much information . Bare in mind I am not talking about dynamics . It is nicely dynamic . For the price its a very.musical cartridge but its musicality comes at the expense of a lack of uppermid and high frequency information . Does the MP150 give me whats missing in the MP110 or in order to get it must the move be towards the MP200 ?