I have the MBT250 with TT65, PS90 and SX100. I also have an old SX70 from when I bought the station but the SX100 is no compare, it works so much better. I dived into it this weekend and the Pace MBT350 including everything I need (including a ton of tips (5 for each size except for the micro tweezers and TM100) sits just under 3000 euros while the same setup for JBC goes way over that. But I do not need a microsolder iron and tweezers and then there is a JBC with hotair, desolder and solder handpiece. But if I stay with Pace I can use the thermojet, SX100 and all tips on both stations (in theory, I have not yet sort out the connector difference) and in case I have one that fails, just when I have a pile of work, I can use the one from the other station. I can buy the MBT250 but that costs more with 3 handpieces as the MBT350 with 5 handpieces
For others thinking about rework tools some thoughts about Pace but also in general:
The Pace MBT250 is sensatemp, a pretty good way to keep a very accurate tip temp. No cartridges but my PS90 outperforms my Metcal (that was a waist of cash) and I do not need the fast auto on/off. The handpieces have a black connector, tips are cheap and very long lasting.
The MBT350 is intellitemp, the connectors are blue and the station can use both modern cartridge and sensatemp handpieces. I do not know if the pinout is the same, if so there was no reason to use an other color. (i will ask Pace for advise, they always advised me great in the past)
They still produce both units but if you want price advantage you buy a base-kit and then add the rest. The same for handpieces, a spare handpiece cost almost the same as one complete with toolholder but if you buy both separate the toolholder alone is around 85 euro.
The SX90 and SX100 use different tips. The 100 tips make contact with the heater over a much longer distance. I think 90 tips will fit the 100 but I do not think the 100 tips fit in the 90. The 100 tips have a trumpet shaped end. For me the only downside. As a test I removed the trumpet from my most used tips and used both versions for several months next to each other. I did not notice difference in performance but without the trumpet you never have to remove a huge ball of solder tacked to the trumpet. I now have removed all trumpets with a file.
Things to look for when you want a desolder gun is the amount of suction and the amount of air but even more important is the start when you press the switch. Pace calls that snap-vac, it takes 150ms to get max suction. This "shockwave" start is important to get the initial moving of the solderblob. Hakko uses some sort of valve technique to get this effect. I could not find that for JBC but I found a video where they compared both (and some better Chinese stations) and the Hakko was just a bit better as the JBC but both where much better as the Chinese ones.
An other thing is durability, tips suffer a lot from things like the moving in circles, bending pins up if they are bent against the board and then soldered, from conformal coating etc. So take the price of tips into your budget for operation-costs. But that is not all. The fliters clog up reducing the airflow. I like pace for this because they are easy to clean (I wash the filters in IPA and now they last over a year instead of weeks. I just switch them but if I have time I wash the dirty ones. I use a little dot of steelwool in the traptube (I use the glass one but have a few disposable carton ones as backup)
In the year I had the Metcal I needed to clean and replace the worn pump membrane a few times (I had two pump units) My MBT250 pump is very old (several decenia) and has a very hard life. I opened it a few times but it looked inside like new and even the membrane was like new. So the filters do a pretty good job and my filter washing does not seem to have a negative effect) I heard from someone Pace used to advise to clean the pump so every now and then by pumping IPA through it (the guy who told me that he connected a piece of tubing instead of the handpiece and then used that to suck in IPA instead of air. It then returned through the hose h connected to the output nozzle and this way pumped it around. I have done this once about 10-15 years ago but the IPA came out as clean as it went in, so I never bothered to do that because opening them also always showed a clean pump.
And for last, desoldering is a technique, it is more difficult as soldering because you have to deal with old solder, coatings, dirt, corrosion, pads that can come lose, vias that can damage etc. Pace has some excellent videos made in the 80's but still very usable. Add solder if the solder will not melt within 2 seconds or so due to corrosion of the outer layer. Conformal coating on top of the PCB is something that can bite you in the b%lls. If the solder melts but the coating not, there can not be an airflow through the hole. The solder melts but does not come out 100% or even none at all. Jus use a needle or scraper or whatever, to remove the coating enough for air to pass through. If a via is torn in 2 the solder will only melt on the side you apply the heat, but resoldering a new part can prevent the solder to flow also to the top part of the via and this way you can get a very bad connection between top and bottom trace.
Never apply pressure, this is the 100% sure way to kill a pad. If it does not melt add some fresh solder
Use the right size tip. Not to small (or solder can not pass) the tip must more or less mach the inner and outer diameter of the pad , it must not wider as the pad because in that case you will not melt anything but the epoxy :-)
Be extreme caution with single layer consumer grade pcbs with no vias. Those pad come loose even if you think about desoldering them. The right size tip and temperature is very important in those cases.
The solder gets sucked straight up against gravity, I often shake the handpiece a bit while I let the pump running. The metal Z strip in the reservoir then moves and prevents a ball of cold solder just above the tip-tube. But if possible I mount the PCB in a 90 degree angle, seems to work just a bit better.
Clean the tips bores. The get clogged with burned flux, coatings, oxides, dirt etc. Do this careful, you must not damage the coating (inside and outside) tip reactivators do a great job to keep your tipsa in shap. I use the stuff from Weller. It coats the tip. I also usd it on my DIY tips (I sometimes make for special situations)