I can't speak to the current specs, but was happy with my dell xps from 3-4 years ago. It is a bit slow to start up now (as with all pcs), but handles revit, Photoshop, etc with ease once it is going.  I think when I looked, it was rated pretty highly by consumer reports. A good sign...

been rocking a macbook pro for about 2-3 years now- 16 gb ram, 512 gb ssd- running autocad lt, photoshop, sketchup, fast as crap starting up even now, and still fast running- higher buy in price, but worth every penny. i never understood why windows slows down over time, but have definitely experienced it...

So I"m speaking from a 2008 Dell XPS M1530 standpoint but...

Negatives

• Dell batteries are notorious for being terrible.  Mine last about a year before they stop holding charge.    Please do your due diligence and research their current laptop battery lifespans.  At $180+ a pop it's an expensive thing to keep replacing.
• Also look into the reliability of their current graphics card.  It turns out the Nvidia 8600GT graphics card that came with my XPS was knowingly faulty (there was a class-action lawsuit I missed out on because I didn't know about it).  I actually just had to dismantle my computer yesterday to remove the GPU so I could blast it with a heat gun to fix cracks in the soldering (after my computer failed to boot and was giving me a faulty motherboard code when running diagnostics).
• My machine runs excessively hot...to the point where it burns to touch on the bottom.  It's done this since I bought it new in 2008 and is common to XPS machines.  Check to see if its true of newer models.

Positives

• The screen is beautiful.  1920x1200 pixels is extremely useful to have for graphics and photography work.
• My 2008 model still runs Rhino 5, the Adobe Suite (5.5), and most other programs extremely well.  It even handles Maxwell Render!
• Although it no longer runs on batteries (I refused to stop buying them ~4 years ago and just keep it plugged in) and has a faulty GPU (that crapped out for the first time on me yesterday but that I was able to fix) I think it's pretty amazing that I'm still able to do full blown 3d modeling and rendering with it.  It has no problem with me editing 200mb image files in Photoshop.  It seems most laptops last ~4 years before they start really slowing down or become completely useless.  
• When I originally purchased it I skimped out and bought the smallest hard drive and spent the extra money on the upgraded screen and graphics card.  When it became necessary (mainly due to space requirements) I purchased a much faster and larger hard drive a few years later ( ~$160 for a 500gb 7200rpm SATA).  If money is tight you could go this route and purchase another hard drive later, probably for a much cheaper price since technology is always improving and out-dating itself.

Overall it's a kickass laptop that handles high loads extremely well.  Look into the battery and graphics card thing.  I would hope they've fixed those issues but you never know...

Also, in regards to computers slowing down.  Mine still boots up extremely quick.  After a clean Windows install with all of my programs installed I created a system back-up image and would revert back to that once a year.  I think that's helped keep my computer stay quick and nimble.

I adore Dell company, in my home 2 dells, one of them is already working for 8 years, no one problem.