the the 555c new holland /ford TLB (tractor loader backhoe) i have. i wish it was a 3pt backhoe. so i could easily disconnect and put on rear implements. BUT. at moment, the farm needs enough things done. that having a single swivel seat with a cab. was much more beneficial for me. for next couple years.
it is a used, but a tuff old beast. once i get majority of the bigger projects done. then i will be trading in on most likely a new smaller size utility tractor in the 40 to 60 hp range. that will do majority of the every day tasks for upkeep and maintenance.
it is a construction model vs a ag/farm unit. but it sure is nice to have.
when i do end up getting a smaller ag/farm tractor, it will need a cab. and majority of the work will be like you, bush hog, finishing mower, maintaining rock drive way and some dirt lanes. pulling some tree roots out, pulling some cut down trees out of the woods to a better spot to be cut up and split. post hole digger for fence lines. small plow,disc,harrow or tiller for landscaping spots in the pastures and yards.
when i get to above point. ya i will be spoiled to have a swivel seat to run backhoe with an all in one cab setup. but the amount of backhoe work that will be needed. will be small. and if it means i need to get out of cab and walk around to bh seat. so be it. ya it will be less convenient. but being able to run rear attachments easier will be more benefit at that time.
about the only thing i will complain about though. is getting my rear unstuck! i have used that backhoe multi times to get unstuck. actually it was more like i was an octopus inside the cab, as i operated FEL, operated gas pedal, operated joysticks for BH. changed gears, etc...and if i had to use 2 seats and/or cab. it might mean i might actually be more stuck than what i thought i would get myself in to.
as far as renting vs having a BH. renting was not worth it for me. when i need it and i need it now. and by the time i call around to find a descent deal, then gas, plus wait time. the BH would of paid for itself and is paying for itself. if i already had good size expensive truck plus 2 or perhaps 3 axle trailer. it might be a different story. but i do not. and if you need shipping to and from your place those added costs add up rather quickly.
some folks save projects up for BH or rather renting an excavator. till they can not hold off any longer. and may rent it for 2 days to a week. ((longer ya have it, more discount you get normally)) if you can do this. it works out better.
but for me, i tend to get into projects. were the BH is needed once or twice throughout the project and until that thing gets done. project is on hold for good. and if i wait around to save up projects. i end up with (a) a big mess (b) wasting extra time cleaning up and getting things nice till that day comes around to renting an excavator or like.