This may depend on the hardware, but after many installations/uninstallations, at least the latest version (8.9.8.48), adds a liiiitle lag to my desktop experience. Meaning, if i rapidly browser through many folders without Lasso, things are a bit snappier. Also, it's not as good as it claims. Running something like Intel Burn Test, i had non responsiveness or poor responsiveness, despite Lasso. It may help at some occasions where you are pounding the CPU, but, if you have many cores and RAM, i think this is placebo from the past. For the record i run FX8350 and 16GB RAM. And under normal circumstances, even if i use 100% CPU with normal programs, the PC doesn't freeze. The only always useful thing from Bitsum, is the unpark utility, for those who have CPUs that park cores and have no other way to unpark them. I use the Microsoft patch for Win7 on mine, so i don't need that either.
Worse is the case of Cleanmem, where if you have plenty of RAM, you 're better without it. If you don't, then yes, it may help. But if you never ran out of RAM, better ditch it. I 've had momentaneous choppy reply in the moments it was cleaning.