The Ademco (now owned by Honeywell) Vista-15 SE is an excellent choice for an upgrade replacement Panel. Ademco/Honeywell has the alarm industry's best record for making their Control Panels and peripherals back-and-cross compatible. That means if you decide to upgrade again a few years, to a Vista-20P Panel, any peripherals (like keypads and RF Receivers) on the SE will be compatible with the P model.
You didn't mention how many Keypads you have on your XL1218, but you will need to replace it/them for the V-15SE. Keypads are brand-specific, and FBII KPs won't work on Ademco Panels.
You will need at least one
6160 Keypad to program the Panel. An older 6139 KP will work, but I'm wary of buying a KP that old, because KPs have moving parts that wear out, unlike most other peripherals. If you have more than one KP, you can replace them with Honeywell/Ademco 6150 KPs. Make sure your
keypad(s) are set at Address 31 (non-addressable mode) before trying to use them in the system.
As I recall, the XL1218 burg zones didn't usually have EOL (End-of-Line) resistors on the
burglary zone loops. For the V-15SE Panel, you'll need either to install 2K resistors (I see some in your picture), or program them as "Normally Closed" so they don't need the resistors. The default programming is for 2K EOL Resistors.
That's for burglary zone loops. If you have (a) zone(s) for fire (smoke/heat sensors) or CO (Carbon Monoxide) detection, this would be the time to mention it: EOLRs are absolutely required for those zones.
I see in your picture that the V-15SE Panel has a 2K resistor wired, in the Panel, to Zone 1, on the negative/ground/Lo side of the loop.. That's how I would wire it for a home system. If your application is for a commercial premises, I strongly recommend putting the 2 EOLR at the end of the zone loop, i.e., at the last contact on the door/window/opening of the loop.
EDIT: Almost forgot: I also had trouble find a specific Vista-15SE Installation/Programming manual, but this one is essentially the same wiring and programming for your purposes.
http://www.alarmhow.net/manuals/Ademco/Control Panels/Vista-15/Vista-15 Installation Manual.pdf