The Ford Jubilee was/is a decent tractor, but the 135/150 Massey Ferguson is light years ahead of them. (I'll get to the differences between the 135 and 150 in a bit) With the Massey's you'll get more power, better over-all gearing, more lift capacity, a long list of possible options, and MOST OF ALL, LIVE POWER on the pto.
135's and 150's will have one of 4 engine options. Gassers had either a Continental 4 cylinder or a Perkins 3 cylinder. Some 135's were offered as stripped down "economy" models. (w/o live power) They had either a Continental Z134 or Perkins AG3 152 (or Perkins AD3 152 diesel) The 135 deluxe (w/ live power) came with either a Continental Z145, Perkins AG3 152 gas, or Perkins AD3 152 diesel. Any of the gas engines are more than capable, very long lasting, dependable, and neither stands out above or below the other. The diesel is the preferred option though. The AD3 152 held Nebraska Test fuel economy records for many years (diesel powered MF150) They run and run and run. It's not uncommon to see them with 8,000 to 10,000 hours on the clock with no major repairs needed. The 3-cylinder Perkins is one of the cheapest engines around when it is time for a rebuild. Complete engine kits can be had for just over $400. Be it a 135 or a 150, the diesel powered ones are the cream of the crop.
Massey Ferguson never kept detailed numbers on the 135's built, but between the Detroit Michigan plant and the Banner Lane plant in England, over 490,000 135's were produced. A plant in France also cranked out serious numbers of 135's too. During their production run, they were the number one selling tractor model in the world. No tractor model has been produced in as large of a volume since. At one point, 1 out of every 4 tractors sold new in England was a 135. They were produced in the US from 1964 to 1975. English plants produced the 135 until 1979. They continue to be one of the most best selling tractors ever on the used market. Their stone reliability, great fuel economy, utter simplicity to maintain, and great parts availability are unmatched.
Both the 135 and the 150 share a great many components. Engine, drivetrain, hydraulics, and MOST of the option list are the same. Both have a 4.6 GPM internal hydraulic pump that operates (depending on a tranny/pto options), from 2800psi to 3450psi. They are MORE than capable of operating a loader. The relatively low gpm flow rate means a loader will be a little slower cycling than some newer tractors, but there are thousands and thousands of 135's and 150's with long histories of successful loader use.
The difference between a 135 and a 150 makes the 150 a much better choice for a loader. The 150 was an off-shoot of the Ferguson F-40 and Massey Harris 50, then later, the Massey Ferguson 50. They evolved from the TO35 into a rowcrop utility variation. The 40/50/150 has a slightly longer wheelbase, which helps with stability under heavy loads on the 3-point hitch. That longer wheelbase comes about as a result of a much heavier front axle and axle bolster. That is of great advantage with a loader also. The different front axle comes with much better power steering which is essentially the same as a 65/165's. With a 150, you get a larger capacity fuel tank, bigger radiator, different air filter and filter location, all adding several hundred pound to the front end. A 150 will handle rear mounted weight much better than a 135. The different axle bolster also provided a strong mounting point for a loader, as well as mid-mounted cultivators. The 150 comes standard with PAVT (spin-out) rear wheels, flattop fenders, full lighting and instrumentation, power steering, and 2 of the 3 different transmission options available on the 135. (Standard equipment on 135's is a 3X2 speed, with 3X2 w/ multipower and 4X2 as options. The latter is standard on the 150 with the 3X2 w/ MultiPower as an option)
The 150 IS NOT the "Orchard model" of the 135. The 135 was available as a standard, deluxe, orchard, vineyard, and industrial model (2135) The 150 came in Standard and High Arch models. High Arch tractors had larger 38" rear wheels with a choice of wide front axle, or narrow front models with either a single wheel or pair of wheels.
I've personally owned a 150 since it was new in 1971, along with quite a few used 135's I've bought and re-sold over the years. WHile I an't attest to the individual condition of each used tractor, in general, IMHO they are the best tractor of their type ever produced. A few simple tools and a basic understanding of how they function and you can keep them on the job virtually forever. They are getting "of age" now, so some of them are getting a little worn down. Find one in good condition that's been cared for and you have a great tractor at a very reasonable price relative to the cost of a NEW tractor in the same size range.