I haven’t used the Hamilton MicroLab Prep, so I cant speak directly to that. There are a few things that you should consider/be able to live with when purchasing an OT-2.
First, I’m not sure what kind of chemicals you are planning to pipette. I’d check out the Opentrons chemical resistance chart to see if you are planning to use any chemicals that “poor” compatibility, particularly with the internal pipette plunger O-ring. I had a group that was thinking about getting one for metabolomics work, but was basically told that we would have to replace our pipettes every year due to the solvents they normally use. The Single Channels are currently running $2,250 and the Multichannel are running $3,250. If that’s something you can afford to do in the event of a pipette failure, then it may still make sense. I’d ask the same question about compatibility of your chemicals with Hamilton too.
Second, you need to be willing to spend a lot of time doing labware calibration on the OT-2. especially if you plan to run a bunch of different protocols, rather than a few specific ones many times, or if you are planning on swapping out pipettes on a regular basis. See this link for how to do a deck calibration, and follow along to see the work required to finish various other calibrations (tip length, pipette offset). You then need to Calibrate labware offsets for each labware on the deck for each protocol. If you run only a few protocols over and over, then these offsets will last you a while. If you plan on running a diverse set of protocols, then the 20 run limit of offsets being saved will require you to do this kind of calibration a lot more often. If you plan on swapping pipettes often, you will have to repeat most of these calibrations when you do that. The 8-channel pipettes are also a little finicky to level just right too, expect to play around with that for a little bit until you get a good feel for that.
Third, the API evolves very quickly, to the point that some features are deprecated or are broken, and its not always a fast turnaround or fix. You’ll have to carefully evaluate each software update, to see if the updates are worth it in that situation.
Not all is bad though! Again, with the Opentrons python API, you can be quite flexible with your protocols and is the only “vendor approved” python language. If you can deal with the issues above, it does work quite well. We use it mostly for qPCR in a 384 well prep, and it’s a little workhorse that performs quite well with it. As long as you stay on top of those calibrations, it was pretty reliable to set up 10 uL reactions in our 384 well plates, and do serial dilutions to dilute the libraries before we load them into the plate. And as you note, there is not a lot of instruments at that low of a price point.
From what I understand, the Microlab Prep would much more of a closed box, and if you do need to flexible, that may be a challenge. I’d conceptualize the exact protocols you want to run, and bring it Hamilton and see if it would be possible on the Microlab Prep.
There’s plenty of content on here if you search for OT-2 or Microlab prep, to see what the common challenges are (or the cool thing people have done with either). Like I said, if you are willing to deal with the issues mentioned above for Opentrons, then it sounds like you are leaning that way. I wanted to post this though so that you are at least aware of its weak points, and that you can make an educated decision!
@Kastronaut , Opentrons didn’t offer service contracts until quite recently. I don’t necessarily think that you need one for an OT-2, I’d ask to see what is included as part of these service contract/PM. We do regular maintenance on our OT-2s, which is just repeating all the instrument/pipette/labware calibration quarterly, as well as replacing the external O-rings on the 8-channel pipettes we use. Unless the service contract is very inexpensive for an OT-2, I’m not sure its worth it if you take good care of it yourself. Ours has been going since late 2020 with no major hardware issues to speak of.