Find an old Vixen FL102S - simply outstanding, and fluorite too
One sold here recentl (Celestron badged)at a good price. Natively f/9 (GREAT for visual), and can be stopped down to f/6.3 with the proprietry (yet scarce) Vixen focal reducer (which I have, and which Claudio still may have a few of - exxy at $250 each, but worth it)
I have looked through many LP's - all terrible! Really, a waste of money.
I used an SW BD 100ED, and it was really good bang for the buck, as was the 80. I was never fond of the 120 - always seemed to show colour abberation. I have also used a couple WO mini-refractors, and again, decent for the price.
Long Perng and United Optics stuff is really average at best. An owner showed me through his over-priced UO 115 recently, and it was ghastly in comparison to the FL102S and the AX103 we had out. Just not good, despite the wild grandiose claims for UO (all hype and no substance)