Well.. the marines & corals much lovely in Semporna & water much clearer than Perhentian & Redang but the beaches are not as clean as those in Perhentian, Redang or even those in Thailand.. I also feel ashame seeing those rubbish everywhere and the sight of those poor bajau laut/tausugs/sulugs (waterworld citizen without clear citizenship or already got dy) waiting for leftover food from tourists

There are no real beaches on Seporna side except the islands such as Mabul, Kapali, Mataking and few more private islands. Try to google for those resorts or read from pg1 or backwards from this thread.

Cheap normally simple and not so clean hotel/ Giuesthouses. and those in Semporna for sure cheaper than those resorts on island side.

Due to budget constraint, I stayed 1 nite at Dragon Inn -Semporna (~RM100/nite) & the other 2 nites in Borneo Global Diving Inn (~ RM40/pax)...Chartered a boat to Mabul, Kapalai & Tun Sangkaran Dandan island for ~ RM350-RM400 per boat/day.

To Sipadan, you need to arange atleast 1 week earlier wth the travel agencies there...Otherwise.. hard to get a permit going there. I did not reach Sipadan due to this fact but you can see Sipadan from mabul & Kapalai.

Staying on islands for sure more premium and price not cheap.. really depending on your budegt.. Do read this thread 1st to get the idea