The Studebaker wins if you can get one under budget IMHO .
If it were me I'd get one of the following and you'll notice a theme
Mercedes W123 -They are quite cool with their looks and are old school in a good way to drive. -A number of spares are available still. -They go reasonably well.
Downsides -Rot. They rot for fun, and given many were workhorses, many were bodged up over time and worked to the bone. But give them a nice coat of paint -The SLS system can give grief but is not too bad to repair if you know your way around them. It's effective when it works -The 2.8 are pretty thirsty but 280TEs are now beyond your budget IMHO for something worth buying.
I also think you'd need to look at the top end of your budget for a car which wouldn't ruin you. While @zelendah's car had an iffy engine, I've seen a few for sale with iffy engines that folks have either taken back or struggled to shift as a result. The engines were unique to the W123s (as one example, the M103 4 pot was a single chain vs. a double chain for the W124. The SLS pump is driven off it, so that creates issues).
W124 Pros -They look cool -They drive very well. They were a huge step up from the W124 in dynamics, while retaining the comfort. There is just something about how a W124 goes down the road. Modern, yet with a nod to the past in many subtle ways -They're large Spares are available easily in good quality and still with a good dealer network for support. -They're not terrible on fuel in the non petrol 6 pot format -The 6 pots in 24 valve petrol form do get a move on well -The 5 speed auto when it works is a lovely gearbox. It's basically a closer ratio box.
Cons -The 5 speed can also be tempremental. It's generally the electrical bits which give grief like contact issues etc. Rebuilds are cheap for them however. -Manuals can be fun with the Merc handbrakes (i.e you can't release them gradually). The 3.2s (E320/320TE) were only available as a dogleg 'box from the factory which can make them tricky sellers. A Merc specialist I know knew of folks who got rid of manual 3.2s due to the gearbox. -Rot is not as bad as the W123s but they can be bad. Common areas are the jacking points which can be a simple repair or the subframe mounts, which are trickier -The cloth can wear on well used examples, and the only source of material is basically other seats.
For me it would be my pick. I may know of one for sale alot under your budget (230TE) if you are interested
To me, the S124s are a much nicer drive than a 740, of which I've owned two, including a
-2.3 GLE K-Jet estate -2.0 SE EFI Saloon Facelift.
Despite having a steering rack, the W124s just get down the road nicer, and are a little less boring to live with. I'd say the interiors are better too in a W124. That said, they can munch up motorway miles reasonable. I took our 2.3 GLE around Europe with a few friends to basically Slovenia, Spain, and the places in between .
Triumph Estates are a good shout, but good ones are now £8k all day long. The 2.0s can be a little slow in auto form, but they are a charming and pleasant thing to drive in sorted form. The biggest issue with these is rust, albeit they seem to be better than W123s, most likely down to W123s being worked alot harder.
I'd love to recommend a BX for their charm and amazing ride. But don't kid yourself on the spares front if the car is to be a daily. Ideally, you'd have a backup car with something like that.
I will soon have a partially built / painted anglia 105e estate I’m considering letting go - 1500 pre Xflow , some Milton goodies . Had it many years but it’s time for it to go soon . Not advertised or ready to go just yet but if it’s of any interest PM me for my number to discuss . 🙂👍