I stayed in the Lake Diamond Hotel last August with my girlfriend and and friend for 2+1 night. We have 2 double bedrooms. With 2+1 I mean that we stayed two nights when we arrived in Pokhara (Mankunmar the owner of the Hotel pick us up in the bus station) and then we went for a trek in the Annapurna region for 3 days and came back to Pokhara and stayed that night in the Lake Diamond Hotel again.
I think that the best thing about this Hotel is that you feel like you are at home, all the staff is very friendly and helpful. The hotel is located very near the main tourist street (just 3 min walking) but far enough so it is pretty silence.
They have very good size double bedrooms with en-suite bathroom with a bath (if you've been in Nepal it might sounds wear that they have a bath but its true) although our was pretty old my friend's one was quite new.
The breakfast is not included so we did not have anything special just toast with honey and lemon tea.
The prize was very good just 5-6 euros the double bedroom (5 for my friend and 6 for me and my girlfriend).
Mankunmar also get us everything sorted for the trek, TIMS and ACAP permits, guide and porter and transport to and from where we started the trek. Also anytime you need a ride anywhere you can ask them to take you (their prize is pretty much the same as any taxi but you dont have to bargain with them).
About the food we could not tell because we didnt have any food in the hotel but the views from the roof are amazing and I guess having lunch there could've been a nice experience.
Overall a great hotel and I will go back to this hotel if I go back to Pokhara.