The XE motherboards had a few flaws that only showed up after they had been released and tested using real software. The main problems were "The DMA problem" and "The USB problem", but there was also the "On-board sound" problem:
The DMA problem: because of bugs in the VIA southbridge (which was designed to run with an x86 bus), there was a problem with data transfers using DMA if the on-board IDE interface and the on-board Ethernet interface tried to send/receive data simultaneously. It can be fixed by cutting a couple of tracks and adding a couple of wires to the back of the board, but it has the side effect of preventing use of the 66 MHz PCI slot for video graphics. A better solution is to use a plug-in PCI card for disk interface - these days you'd be better off with a 2- or 4-port SATA card, anyway. As long as the card has a 3112/3114/3152 chip set, it'll work OK with existing drivers.
The USB problem: because of lack of documentation of the VIA southbridge, terminating resistors for the USB ports were omitted from the motherboard. They can be added easily by anyone with a soldering iron and good eyesight. The four USB ports on the board need to have a resistor of 12-15 kOhms connected from each data line to ground. These resistors are usually added on the back of the board, soldered across the pins of the sockets. Some people have removed the 47 pF EMI caps from the data lines and replaced them with SMD resistors, but that is a tricky job unless you are experienced with SMD.
The On-board sound problem: when the XE board was first released, no one could get the sound chip to work, so it was assumed that there was a wiring fault and it was left off the later manufactured boards. Later still, it was discovered that an undocumented enable bit in a southbridge register had to be turned on to make it work. If you are lucky, you might have an early board that had the sound chip installed. If yours is a later board, the sound chip can be added afterward by someone who knows what he is doing, but it's fiddly and the on-board sound is only average in quality anyway. A better solution is to use a plug-in audio card.
If your XE is "flakey" (and a lot of them were), it may be because of the memory. I've tested and worked with a lot of XEs, and they all behave differently. Some of them will run with two memory DIMMs, but most will only run reliably if you have a single memory DIMM installed. It is getting harder these days to find suitable memory for the XEs (it's old technology now), but you should be able to find a 512-MB DIMM at a second-hand market or on line. I would advise against trying to use two DIMMs - you'll likely get better reliability out of a single.
The mounting of the CPU module is another cause of problems. The CPU module is supported on two M3 tapped nylon spacers that are too long, and the CPU module sits crooked because of it. If you (or a kind friend) remove the spacers and cut about ½mm off each one, you'll be able to get the module to sit parallel to the mobo and it might cure some intermittents.
Lastly, the XEs are famous for being very touchy about their 3V clock cells. The voltage of a new one is usually about 3.2 V, but once it falls below about 3.0 V, the machine crashes or won't boot properly. Fortunately, they are cheap and can be found at any supermarket or chemist/drugstore/pharmacy.