RoG full fat version cannot pakai for work (attention too great and too heavy, why cuz i owned 1), but the slim 1 will be cool/awesome in meetings and so.
As for Dell rep, Yes i agree that they suck badly last time, but i gave them a chance to renew themselves as the builds they are making so far seems to get better and better.
The inspiron 15 5000 is not gaming grade but for normal office use (word, excel, and basic cad process) RM2.7k (I asked for special discount)
The inspiron 15 7000 is mid tier gaming used for graphical works, cad, etc which is more than sufficient. RM3.8k (which went to RM4.2k later)
I must say that the the build of Dell has improved sufficiently and have some nice features like bios lock out, which is useful to lockdown the hhd and motherboard cpu in case of raids

the cons is that their software x hardware is still a mess as drivers are mostly proprietary and the default win 10 setup is farked up (drivers, software, running backgrounds, etc)
I had to wiped every driver out and reinstall back, cancel every hidden background in windows (xbox, alarm, phone, messaging, tablet, etc) to make the laptop work better.
but overall my N53SN is still my main workhorse which never crapped out (the build is awesome as always) but I am currently looking for an upgrade soon.
I would say that after >4 years a 3.5k laptop will pay off itself for normal usage and 2 years if for productivity.
And if you do heavy render works in the office, a 4.5k laptop will payoff easily due to the time saved, and the infrequent crashes of GPU/CPU.
The xps 15 6k-7k, i do agree it will need super justification for it to pay off itself, but you will benefit from the long running services of updated drivers from dell, which might be important.
Have never seen slim RoG, the ones I see are gila heavy and edgy. Will have to walk walk in mall to see, still quite doubtful whether will be suitable for work environment.
Software is not an issue to me as I don't use Windows (work is all on Linux and related anyway since years ago). So I look basically for solid hardware, no 'special' things, and drivers aren't a big deal.