Ikea do tend to be unique. No service void at back of units, deeper than usual base units, 600 rather than 575mm, requiring a 635mm worktop to give any overhang over the doors. I'm guessing whoever cut the tops went wrong setting the jig for the unusual sizes hence the misaligned mitre joint in the picture.
I've never known anyone, myself included, who having fitted an Ikea kitchen, would ever consider installing another one.
I'd do it again but as I use the cooking stuff from time to time part hobson's choice.

I know my wife and I'd hate poking about in normal cupboards. She has filled the lot up.
Services - not really a problem. There is room low down at the back. Mine come down in a corner boxed in and run from there. Gas and water. Square walls etc can be a problem especially on floor standing so rather than a rail it's better to use brackets.

I needed one dead vertical wall where what is left of an internal wall is so created it. Ikea suggest leaving a certain amount of space and using a scribed filler for that sort of thing. In my case that would have messed up the layout.Some use brackets on the wall cabinets as well but I've found the rail is ok. Some packing may be needed but even with a bit of dish in the wall it's worked out.
There is some scope for worktop overhang using Ikea worktops, Not much though - more sticking out a little past the doors. Some can be lost scribing to walls.

The joint - it's ok not glued and bolted when I took the shot. Glad I found out how a kitchen fitter use the jigs though. I did a U and was bugged about walls being out of square.
I would knock Ikea on 2 points. Stupidly deep wall cupboard and pan drawers are rather deep as well. I may ditch one and fit 2 shallower drawers. I toyed with the idea of cutting the depth of the wall cupboards down but didn't. Ikea say worktop lights are good idea due to this but I have fitted a number of ceiling lights more or less directly over head from where people will stand and shadows haven't been a problem.
As an old house and crap work done for various reasons on some plaster work I'd take the lot off next time rather than trying to sort it out before fitting. If I was lucky enough to get a good plasterer in though that aspect would have taken a lot less time. Where the original plaster hadn't been worked on it was fine.
LOL I still haven't done the tiling. Decided to have a break - that is getting a bit too long now really.
All in all with floor levelling and other bits and pieces such as the electrics it's a lot of work especially if the kitchen needs to remain usable throughout. On the worktops I needed a router and saw update anyway. Otherwise that part is probably best left to a professional. but the rest still needs to be correctly positioned etc.