I live in Cambridge, and commute to a mix of Liverpool Street and King's Cross.
Honestly? I actually quite enjoy my commute. It's long enough to 'switch off' or get something done/read along the way. Plus it's resilient - if one route goes down the other route is there as a back up (storm Doris was the only day in the last few years where both routes were sinultaneously disrupted for a significant duration)
On the Kings X route, you get a good fast blast on the ECML, then enjoy the slightly rolling fields as you head through Royston.
King's Cross trains can be busy at times, and sometimes elbow-y/bargy to get on, particularly for the evening peak trains that have shorter turnround times. But there are 'good' trains as well, which you'll learn over time. Some trains are elbowy to get on (e.g. the 1814), but I've found that there's still plenty of seats anyway, so let everyone else have the petty fight first, then just get on behind when they've sorted themselves out.
Morning peak is generally fine - never not got a seat at Cambridge. Only difficult trains are the 0815, plus occasionally the 0745 on a particularly busy day if you turn up at the last minute. Homeward, the 1644 is always crazy busy - most other trains less extreme (although Fridays can be noticeably busier)
One thing you will notice is the difference in frequency from Cambridge compared to Bedford - you effectively only really have a train every half hour in the peak. Might take a bit of getting used to.
Also, it'll depend on where you plan to live in Cambridge and how you plan to reach the station. Driving and buses are not always recommended, particularly on the occasional evening when Hills Rd gets completely snarled up. Alternatively, walk or cycle - dead easy around Cambridge. Don't forget Cambridge North also opens next month, served by around one fast King's Cross train every hour for most of the day.
Hope this is useful.