As a SLP-98 owner, a few thoughts. First, there are least 3 different old and new versions of the 98 I’ve heard personally. Each build with/wo upgrades sounded different. Some of this is due to different vintage or modern 6SN7 dual triode tubes used, different upgraded coupling caps inside, and different volume quality volume controls selected. Various upgrades were offered over a few decades. A colleague sold his very early 98 version for a new updated unit a few years ago, and likes it quite a bit. It displaced a well known $17k preamp he resold and kept the new 98..
Your Krell is a nice piece for sure, and was well regarded when it came out and many years later. A completely different design of course. Both are sensitive to good interconnect cables too, fwiw. It becomes a preference decision IMO.
Other may chime in with different experiences and recommendations. Good Luck.