We spent three nights at this hotel and it fit our needs perfectly.
The Sleep Inn & Suites is conveniently located off I-25 and just a few minutes to the newest shopping and restaurants in Casper.
We had rooms 323 & 325 (connecting) right off of the elevator. Surprisingly, we didn't have any noise issues. The entire hotel is going through a renovation phase so there are areas that are still being worked on. From what I could tell, they weren't renting out any rooms on the ground floor as those were being renovated. Our rooms however looked like they had just been renovated and still had the new paint smell. The rooms were comfortable with nice colors. The shower was surprisingly good and we enjoyed the super comfortable beds.
The pool and spa was nice and was hardly used by anyone else during our three night stay. The pool was at a perfect temperature while the spa was overly hot one day, and luke warm another. I'm guessing that the spa had just been drained and was still heating. The fitness room was basic, but the equipment seemed "clunky". The treadmill wouldn't lower the incline (continuously showed an error on the screen) and the eliptical was not smooth. Not a big deal at all as we only used it one day.
Breakfast was basic with mini-muffins, danish, toast, english muffins, waffles, hardboiled eggs, hot and cold cereal, yogurt, coffee, juice, and milk. We had to leave the hotel fairly early in the morning so this worked perfectly. If we were staying for a longer length of stay, a few more hot items would have been nice. The breakfast attendant was super friendly all three mornings!

Now just a few minor areas that could use improvement -
Our rooms had obviously not been vacuumed as I found a straw under the desk and the dark carpet showed things that could have easily been picked up with a vacuum.
A small flaw when it comes to lighting in the rooms. Most of the lamps are using eco-friendly light bulbs, but are too large for the lamps. The bulbs are lower than the lamp shades which then gives off a glaring light throughout the room, leaving the shades virtually useless.
My last comment would be that there was rarely anyone at the front desk each time we walked by. When we first checked in, there was someone in the back office but we had to make a noise before they acknowledged we were there. I noticed this with multiple guests checking in/out as they waited for long periods of times. Being a hotel manager myself, I would want the front desk staffed at all times.
Also the business center could use some upgrading as the computer was extremely slow and continuously froze when simply opening Internet Explorer.
None of these comments are deal-breakers by any means. We received an excellent price and the staff is genuinely friendly. While it's not the newer, higher-end Holiday Inn on the opposite side of the freeway, I feel that this property offers a much better value for the cost. I have no problem booking this hotel again, thank you for a great stay!